First Warning Signs that your Neon Tetra is Dying 121

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The Neon Tetra is one of the most popular fish species among hobbyists. This particular species has been collected by aquarists for more than eight decades now. The neon tetra’s striking iridescent hues and peaceful quality makes it an excellent addition to a non-aggressive aquarium environment.

The neon tetra is a tropical fish that originated from countries in the northern part of South America namely Brazil, Colombia, and Peru. The largest concentration of Neon Tetras may be found in the world famous Amazon River Basin.

Neon Tetra Characteristics

Neon Tetras are small freshwater fishes that belong to the Characidae family. Its scientific name is Paracheirodon innesi and shares some qualities as that of other fishes under the tetra family.

In terms of color, the Neon Tetra boasts a vivid red, silver, olive green, and blue body color. It also features a transparent fin and tail presentation.

Neon Tetra boasts a vivid red, silver, olive green, and blue body color (Img Src:flickr)

Neon Tetra boasts a vivid red, silver, olive green, and blue body color (img src: flickr)

The Neon Tetra’s blue and red colors actually do not extend along the entire length of the body. The blue coloration starts behind the eye and terminates in the adipose on the top half of its body.

While the red coloration starts where the blue coloration ends. The red portion meanwhile covers the lower portion of the body and covers up until the caudal fin.

A fully-grown adult Neon Tetra can only achieve maximum length of 1 ½ inches.

Two of the most distinctive characteristics of Neon Tetras are:

  • Spindle-shaped body
  • Blunt nose


Care and Habitat

Neon Tetras do very well in soft and slightly acidic water. Putting them in water with higher pH will make them more prone to catching diseases. Higher pH levels will make them lose their vibrancy as well. Neon Tetras have little has little to no negative effect on the quality of water in an aquarium.

The water chemistry, temperature, ammonia, and nitrite levels for Neon Tetras are as follows:

  • pH preference: 4.0 to 7.0
  • Temperature preference: 73 to 79 degrees Farenheit
  • Salinity preference: 1 tablespoon per two to ten gallons
  • Hardness preference: soft

When it comes to their surroundings, Neon Tetras prefer to have driftwood and plants all around them. These elements will not only serve as decoration, but as habitat for Neon Tetras too.

Neon Tetras prefers driftwood and plants in their surroundings (img src: Flickr)

Neon Tetras prefers driftwood and plants in their surroundings (img src: Flickr)

In terms of food, experts recommend to alternate between standard fish pellets and live foods once or twice per week.

Common Symptoms that your Neon Tetra is Dying

In general, Neon Tetras are hard creatures in that they can live up to 10 years under a favorable aquarium environment, which makes it a great freshwater fish for beginners.

However certain changes in water chemistry, temperature, stress, and disease can overwhelm Neon Tetras and lead them to irreversible death.

There are a couple of signs and symptoms that Neon Tetras manifest when they are ill.

Here are some of them and the interventions that you can perform to treat them accordingly:

Stress and Acclimatization

A few of the Neon Tetras you just purchased died after a couple of hours swimming in your home aquarium.


API Stress Zyme

In this scenario, water quality may not have been matured enough. Water with insufficient friendly bacteria can lead to the development of toxins in water as waste products are not synthesized properly.

One option is to add Stress-Zyme into the water to aid in the water maturation process.

Salting the water may also be a viable solution. By doing so, you are reducing the chances of disease spread across all your fish species in the aquarium.

If you still have a couple of Neon Tetras left, it may be best to quarantine them in a separate tank. This is especially necessary if you have other fish species swimming around the main tank. The reason for the quarantine is to make sure that the disease does not spread to other fishes.

Restless And Sits At The Bottom

In this case, your newly purchased Neon Tetras may be suffering from tank shock. Your fishes may have initially failed to get used to the water in the new aquarium.

Tetras that seem to only swim at the bottom may be suffering from tank shock. (img src: Flickr)

Tetras that seem to only swim at the bottom may be suffering from tank shock. (img src: Flickr)

To remedy this situation, you will need to acclimatize your fishes first. This can be done simply by letting the bag of Neon Tetras float on the aquarium water. Slowly introduce aquarium water into the bag every five minutes for at least an hour. You may then transfer the Neon Tetras after an hour of this acclimatization process.

Abnormal Swimming Patterns

Checking the pattern by which your Neon Tetras swim is an easy way of detecting if they are sick or otherwise. Examples of unusual swimming are as follows:

  • Fishes swimming like they are “drunk”
  • Fishes swim in circles

Fishes drift with the current inside the aquarium

There are also instances where your Tetras simply sink to the bottom of the aquarium without having the ability to raise themselves. There are also cases when Neon Tetras float at the surface and are unable to swim further down the tank. There are also cases when fishes swim upside down due to severe health problems.

In this scenario, it is best to separate the sick fishes by transferring them to a smaller bowl. Observe their movements for the next 24 hours.

If their swimming pattern does not go back to normal, it is best to seek the help of professionals from the pet store. They will most likely provide information about the probable cause of such an abnormal behavior.

Neon Tetra Disease

Neon Tetra Disease involves the occurrence of protozoan invasion. As the name implies, this condition was first observed among neon tetras.

However this is the case, other fish species can contract the disease too. Signs and symptoms of this disease are as follows:

  • Fish loses coloration or experience color dullness
  • Restlessness
  • Development of cysts as evidence by a lumpy body
  • Unusual spine curvature
  • Fin rot and bloating

Unfortunately, there is no known cure for Neon Tetra Disease. The only thing that you can do is quarantine those who are infected. In this way other fish species will have minimal to no chance of contracting the disease too.

What’s Your Experience?

Have you had any experience in keeping Neon Tetras in your home aquarium? Share your experiences and tips with other fellow hobbyists in the comments section below.

About Dennis Hanson

Dennis is an experienced aquarist with many years of knowledge and experience in keeping successful tanks. He also has no relations to the pop group Hanson.

121 thoughts on “First Warning Signs that your Neon Tetra is Dying

  1. Reply Diane Jan 8,2014 10:27 pm


    I’m wondering if my neons have neon tetra disease. I noticed a few tiny white spots and am adding medication the tank daily for ick. Today their color is faded.

    If in fact they do have neon tetra disease, and I lose them all, how should I clean and prepare the tank for any new fish? Is there a specific protocol for cleaning a tank that contained infected fish?


    • Reply Dennis H. Feb 15,2014 2:06 pm

      Hi Diane,

      Those fish doesn’t have Neon Tetra Disease, I think that’s just ick.

      Usually with raising your temperature(29°C) to erradicate Ick, but Neon tetras are better in cold water(around 22-26°C).

      Move infected fishes to a quarentine tank and raise the temperature slowly.

      How many died? Tell us which tank mates they’ve and I will tell if they are suited for that temperature, that’ll erradicate ick from your main tank.


    • Reply jennifer ziegler Aug 13,2016 7:16 pm

      hi my name is jennifer and i had 4 neon tetra this summer. 3 of my neon tetra go stuck in the filtter. what sould i do. i now have to big tetra. my pink tetra kepp laing at the bottmed. what sould i do about my pink fish

  2. Reply Renier Jan 12,2014 4:37 am

    Hi Diane,

    Neon tetra and other fishes are prone to what they call fungal infections, as what you have mentioned, they have some white spots which are also itchy that lead to fading of their colors. One thing I did before to my tetras: I put methyline blue, or some anti-fungal drops for my pets, I did it for like 3 days to 1 week. On the 2nd day, their white spots suddenly decreased. It is also possible that your other fishes on that tank will be contained as well if you do not treat the infected ones immediately… I hope this can help you out!

    • Reply Diane Feb 28,2014 12:38 pm

      Hi Renier,

      Thanks for the information. I used an herbal ick medication that worked well, but it’s good to know of other options too like the methyline blue you mentioned. I only have 3 neons in a 5 gallon tank, so separating out sick ones wasn’t necessary. I’m also a little leery about separating out fish into a small tank without a heater – all the heaters I see are for 5 gallons and up. At any rate, things are fine now and everyone seems healthy.


  3. Reply Hart Jan 21,2014 10:01 pm

    The image with the caption “Neon Tetras prefers driftwood and plants in their surroundings” – aren’t those cardinal tetras since the red is full body length?

  4. Reply Jessica Jan 23,2014 4:58 pm

    I lost 4 tetras right after I set up my tank, which is to be expected, according to Petco (and other sources). 1 lived and seemed fine. He had several other non- tetras in the tank with him. I really had no idea anything was amiss although I never saw him eat like the crazy guppies do. I did notice an accumulation of brown slime suddenly growing on tank items that a guppy was eating. Anyway, poor tetra #5 was dead today too. I am sorry to hear they can live up to 10 years. Mine didnt even make it one month. According to the water dipstick, all levels are safe, maybe slightly alkaline, but that’s how tetras like it I read. No more tetras for me. Guppies seem hardy. Guess ill stick with them. Thanks.

  5. Reply Vicky Jan 30,2014 2:37 pm

    I’m assuming neon tetras are delicate fish. 8 months ago I bought 6. 4 died within a week. I stayed with the remaining two for the course of the 8 months and decided I would buy more once the aquarium has maintained good water quality for at least 6 months straight. I really like these little guys and I remembered about 10 years ago I had some neons that actually were breeding in my tank and I had plenty babies. I was hoping to have that again. 5 days ago I decided it was time to buy 4 neons. I so far 2 died and to day one is swimming upside down in circles and the current takes him around and water flow of the filter pushes him down. I’m guessing he’s already a gonner and I separated him from the rest of the fish. Is there something very special that these little guys need in order for them to thrive?

    • Reply Dennis H. Feb 15,2014 2:00 pm

      Hi Vicky,

      The Neon tetras are quite delicate fishes. They tend to be eaten by bigger fishes and be sucked by the filter. Tell me about their tankmates and the size of the tank. Before you feed them I suggest wet the food. Dried comercial food has inside air (That´s why food floats in the surface). When the neon tetras (Tiny fishes) eat those microbubbles inside the food tend to float, sometimes upside down.

      Also, make sure to acclimate really slowly. This ensures that they accustom correctly and they don´t suffer shock by the change of parameters.

      Good luck, Best Wishes.

  6. Reply lizzy Feb 24,2014 4:51 pm

    I am new with the fish thing but I bought my 3 year old son some yesterday. I didn’t know I was supposed to acclimate. And wasn’t sure about how long to wait to add them after adding the water treatment… I couldn’t find anything on directions so added them after about 10 minutes :/ I have 5 of them along with a sucker fish and one other but I’m not sure what it is (its dark grey with red fins) medium size… its been about 14 hours and none of them have died yet but they are all swimming at the bottom of the tank and seem to be in distress swimming back and fourth quickly. Is there anything I can do and are they probably going to die?

  7. Reply zio ledeux Mar 4,2014 6:44 am

    hi, i have just noticed 2 tetras that have white spots on them but they are not flat white spots but raised. any idea what could be the problem?i have only ever noticed this on tetras, thanks

    • Reply Dennis H. Mar 10,2014 6:14 pm

      Hi Zio,

      It sounds like ich. Do they show any sign of illness? Swim up side down or anything else? If it’s Ich raise you temperature to 30°C slowly. See if that helps, good luck!

  8. Reply Sharifa Mar 11,2014 5:42 pm

    Dear Dennis,
    One of my Neon tetras stopped eating about 5 days ago. At first, I noticed it stopped swimming with the rest of them and was hiding all the time. It wouldn’t come out to eat with the others. After two days of this, I removed it from the tank and placed it in a quarantine tank. I have been treating it with TETRA General Tonic and I’m doing daily 50% water changes. It seems to have trouble swimming as well. Sometimes I think that its tail looks a bit bent, but perhaps my eyes are tricking me. It is definitely not swimming like it usually does. Mostly just hangs around in mid-level or hides under the aquarium decoration. It is still not showing any interest in food. It has grown so weak. I honestly don’t know what’s wrong with it or what to do about it. The guy at my local fish store didn’t have any answers for me. Just told me to use the general tonic.
    Any advice you can give me would be greatly appreciated.

  9. Reply Debbie Mar 15,2014 2:49 pm

    Hi Dennis, I have a new 64ltr aquarium, we introduced 3 neon tetras and 3 harlequins on 13th and they seem happy. This morning one of the tetrss was missing so checked tank it seems that it got caught in the filter and died. Is there any way to prevent this happening and us there anything I need to do yo the water when a fish dies?
    I have no plants or pump are these necessary in a tropical aquarium?

    • Reply sniffindaisies Apr 8,2015 2:37 am

      Debbie, get a pre-filter… It’s a tube-shaped sponge that slides onto the water intake pipe, and it blocks small fish from getting sucked into the filter.

  10. Reply Leola Apr 17,2014 8:07 am

    Oh my goodness! Impressive article dude! Thank you so much, However I am going through
    difficulties with your RSS. I don’t understand why I cannot join it.
    Is there anyone else getting identical RSS problems?
    Anybody who knows the answer will you kindly respond?

  11. Reply irshad Apr 20,2014 5:32 pm

    Hi Dennis,
    I have the usual neons and black neons in my planted tank.I
    But slowly my usual (blue+red neons )fading their color and becomes lean lower body compared to upper.till now I lost four tetras.other fishes in the tank emperor,black neon,blue neon and hockey stick.Fortunately others are healthy.I’m keeping the temperature at 29.
    Is it neon tetra disease?
    Y it affects only for the usual ones?
    What r the remedies?

  12. Reply isabelle Apr 27,2014 8:44 am

    One of my Neon Tetras seemed to be pregnant but soon after its belly went down and was normal….However it was stuck between the tank wall and the filter and I could get it out safely but xit stayed on the floor and didnt move from the spot. It started to move but wouldn’t stay with the other fishes. What should I do??? And what should I use instead of a heater because I can’t afford a heater. Thanks…

  13. Reply isabelle Apr 27,2014 8:52 am

    What can I use instead of a heater and my neon tetra was stuck between the filter and the tank wall and wouldn’t stay with its buddies…. it stayed on the floor and I still managed to move it but it is not moving as much and it has gotten whiter.. what should I do on this case?? I can’t quarantine it since I don’t have another tank and really desperate. Thanks.

  14. Reply SJ May 15,2014 6:37 pm

    If you cannot afford a heater you shouldn’t have brought tropical fish….

    I have 15 neons, they all have swollen bellies I noticed today! They seem happy and full of colour, eating well and exploring the tank. I presumed maybe holding eggs but this tetra disease has me worried. Never lost a single neon from day I brought them, and I’ve raised a paltie fry so my water cannot be bad otherwise the fry would have died… how do I tell females and males apart?

  15. Reply Jeff Jun 4,2014 12:21 pm

    We are new aquarium owners. We started with a 10 gallon tank with 5 neon tetras and three male guppies. All is well for the most part. We had 2 of the tetras and one of the guppies (not all at once) get caught tail-first in the filter that came with the starter kit tank. At first we thought the fish were just too weak to swim out of the suction. But then we noticed that each time, it was the exact same part of the filter. So we put a plant in front of that part of the filter to diffuse the suction some. This tactic has worked so far. The fish can’t get close enough to get caught.

    But the other issue is I’ve noticed that at certain times of the day, usually late in the evening, the neons get dull coloration. You mentioned that it could be a sign they may be sick. But their color comes back nice and bright in the morning and during the day. It seems this may be a normal thing based on activity. Is it?

  16. Reply Jo Jun 7,2014 3:40 am

    I have had my tank for approx 2 years. I have 1 tetra that is “quite chubby” and it’s eyes have gone … Grey… The eye is no longer black; actually a couple of them have eyes like that. the fat one has a lower lip that is quite pronounced… Is this an older fish… Any info here?

  17. Reply Jo Jun 7,2014 3:45 am

    I also want to add that they are all swimming we’ll and eating, just curious as I can’t find any info on this

  18. Reply Dev Jun 22,2014 5:59 pm

    Hi, i think my neon tetra got neon diseas. Her spine got curved and lost her colour as well. She is not eating anything. I have lost toatl of 5 tetra due to i have quranine one of dm. Any idea if onther mates would hv got ds disease ?

  19. Reply Hailey Jun 24,2014 7:26 am

    Hi, I just got 2 regular neon tetra’s today around 7:00pm and around 9:00pm one had died. Inside the bag it was just chilling at the bottom, I thought it was normal. Then when I was able to put it in the actual bowl (a round, 1 gallon goldfish bowl with nothing special such as a heater or pump) it kept swimming straight up. Stayed at the surface, acting odd, and sometimes swimming upside down. The fish did that until its death. When my mother got home it was at the bottom of the bowl, taking its last gasps of “water” and then it died. I took it out just in case it was ill. So it wont get the other fish sick. I am going to try to get a new healthy neon tetra tomorrow, hopefully for free as a type of exchange. Do you know what was wrong with it?

  20. Reply Kristy Jun 24,2014 12:47 pm


    Neons are a tropical fish they need a heater and a filter! The only fish that can live in a bowl without aeration is a fighter fish, may I suggest one of those instead. Good luck.

    • Reply LilyBelle Apr 6,2015 5:04 am

      Actually, Betta Fish (also referred to as Fighter Fish by some)also should have a filtered Aquarium and must have a heater since they prefer water between 76 and 80 degrees Fahrenheit! So the only fish I can think of that does not require a heater, but still requires filtered by a pump water is a Gold Fish!!!

  21. Reply Hailey Jun 25,2014 1:10 am

    Thanks for the information. I will buy the water heater and filter, hopefully the one that I have will survive for a while. Also I am buying more neon tetra’s so the one I have wont stress. Thanks again!

  22. Reply Rose Jun 27,2014 4:37 am

    Hi there. I have a long 20 gal tank with 1 ADF, 2 Mollies, 1 balloon belly molly, 2 male platys, 3 female platys. Today, I brought home 8 neon tetras. After they sat in the bag, in the tank water for a while, I added them to the tank. Now, I can only find 7! I have a pre-filter over the intake tube so I know it didn’t get stuck in there, but I can’t find it! Also, I think the ride home must have been super stressful as one of them was swimming upside down when I got home. Will he get better?

    • Reply john Oct 3,2014 1:18 am

      gee i am sorry rose but as i read a lot of comments it infuriate me to no end,
      i see a lot of you making a mistake of trusting your aquarist if there is any fisk in his tank that look sick DON’T BUY FROM HIM.FISH SHOUND NOT DIE ON THE WAY HOME from the shop if you have a sick trtra throw him out becase he will kill the rest of them and a fish dose not look right trust your gut felling.

  23. Reply Kbittersweet Jul 3,2014 4:37 am

    Can I point out betta fish fighting fish live in HOT country’s they must have a heater and room to move they also are not good fighters even know the name says other wise my fighter had never picked on one fish on my tank also swims in to ur hand in the tank tetras seem to die on me I’ve given up on them no one other fish has died and I’ve got Molly’s guppys and guppy fry a betta fish couple loach a albino cat fish a pleco red tail shark golden sucking loach also betta fish are also bad swimmers so a fast current is not good for them

  24. Reply Rigoberto Jul 16,2014 8:38 am

    Your style is really unique in comparison to other people I’ve read stuff from.
    Thank you for posting when you have the opportunity, Guess I will just book mark this blog.

  25. Reply Taylor Jul 18,2014 3:16 am

    My neon tetra has turned white, is floating in one spot, and has bulging eyes. What is wrong with my fish???

  26. Reply Mike Oct 19,2014 4:30 pm

    Hello, Dennis –

    I thought I’d run this by you and see what you think. I have a relatively new 10-gal setup (my first in about 30 years!), and I’ve been very careful about getting it cycling before adding fish. The tank gets a 20% change every week, and I always check chemistry just before the change. The water is consistently pH 7.4-7.6, and NH4, NO2, and NO3 are 0s. I ensure chlorine/chloramines are first removed from the tap water I use, and it’s heated to temp (approx 77) and aerated before using. I started with a few Panda Corys and Pristella Tetras, and everyone’s done great for over a month. I then added 4 neons from my LFS. I lost one the first day, but the other 3 did fine, so I attributed it to chance. However, in the last week I’ve lost 4 more (this includes replacements to the originals). In all cases, their behavior appears absolutely normal – eating, swimming, schooling, etc. No overaggression by other fish that I’ve seen. Then, I’ll notice that one is swimming listlessly and keeling to the side, and this one is dead the next day. I’m at a loss, except to think that the pH is perhaps a bit high. No problems with the Pristellas or Corys. Any suggestions would be helpful. Thanks for your time.

    • Reply Dennis H. Oct 30,2014 12:36 am

      Hi Mike,

      As the other fish are doing fine, it seems to me like a case of neon tetra disease. This disease is especially common when the tetras are stressed, and seeing as they are new, they would almost certainly have some level of stress. Unfortunately, it can not be treated.

      It is possible that they have a different infection than neon tetra disease, so if possible you could set them up in a quarantine tank and treat them with antibiotics. Assuming that this disease is neon tetra disease, I would recommend setting up a quarantine tank for new arrivals so that they do not infect those neon tetras in the main tank.

      You could also try obtaining neon tetras from another location. Hope that helps.

      • Reply Mike Nov 5,2014 12:53 am

        Thanks, Dennis. I’m betting that particular shipment of neons was problematic, although I haven’t followed up with the LFS yet. Unfortunately, it is the only LFS near here, and my alternative sources are Petco and PetSmart. Not necessarily a bad thing, I guess, but I was trying to support the private business. No further casualties. I’m going to leave well enough alone for another few weeks before doing anything else. Thanks again for your time.

  27. Reply Lucy Nov 5,2014 2:16 pm

    Sad day today. I’ve had my 10 tetras for almost 3 years now, and yesterday I noticed my heater wasn’t working so I went to Petco and bought a replacement. The same 100w for my 26 gallon aquarium, preset to 76 F. This morning, I didn’t see any fish swimming…they were all dead on the bottom. I don’t have a thermometer but it feels like it used to, not too cold or too warm. What could have happened, and what should I do now for future fish?

  28. Reply chris Nov 9,2014 12:00 pm

    I started with a male and female beta the male beat the fem badly and killed the female in less than a day so “”males do not attack female’s was not true in my case. Ok to the real story my tetras were the bigger fatter kind two yellow a pink and orange they were all so great the first 3 days but then one of the yellows was just swimming straight into the gravel I immediately knew it was abnormal the other yellow one would even come over and try to nurse him and get him moving but he would just sink, the healthy yellow stayed with the sickly one till it passed. But he started the normal routines gain so I was relived till I saw her swimming into the corners for hours and hoa matter ours. She would purposefully get stuck and I knew it was only a matter of time but the Orange and pink loving it and love to come out of hiding to show off. But do the yellows have more issues or perhaps I split the pack and losing him was too much.
    Sad and open to suggestions,

  29. Reply Dennis Dec 13,2014 5:16 am

    I have 6 tetras and I have noticed today they have white spots on them, I read in the previous comments that it’s ick and that I need to move the ones with it to a different tank and I have, but how do I raise the temperature slowly because my other tank doesn’t have a heater, I’m worried because 5 of them have it and I am going to get some medicine for them tomorrow but what kind do I get? And how long will my fish last if I don’t get the medicne to them right away?
    Much, much appreciated!! -Sarah

  30. Reply Ann Dec 30,2014 5:15 pm

    Hi all,
    I have had some run ins with neon tetra disease. I had two tanks with neon tetras in them and wanted to get a bigger school. I moved the two tanks into one so that there was one larger school of neon tetras. They are two years old or so and doing great.

    Immediately, I bought a 2nd school of neons to go in the first tank where the others had lived successfully for two years (well kept). I acclimated them properly but when I put them in there, they began to die almost immediately. I purchased a few from a diff source when I thought things had stabilized but they all died within a week. I suspect neon tetra disease because they were all healthy looking at first. Several of them developed a spot on their side that spread. It was not ich. This was like someone had peeled the color off of the fish and the white spot caved on on the side, causing deformity. This spread through the fish within a few days and many more died. I lost 15 fish total.

    I stripped the tank down, washed and cleaned it well, started with new gravel and kept the same filter. So far four days have passed and the new neons from a diff location than the first are doing well.

    My original neons are doing well in their combined tank too with no problem.

    I want to mention – some pet stores treat their fish tanks once a week- you need to find out when and if they do as any chemicals in your tank could conflict with the fish and kill them too.

    Can the snail that was in the neon tank where they died spread the disease?

  31. Reply Rebecca Jan 13,2015 9:31 pm

    I have a lot red neon tetras but one of them is swimming strange.
    It looks helthy and happy but it ses like it jeeps floating up to the surface. It is trying to swim down bit it is keep floating up! It is maybe a little fat but i dont know whats wrong.
    Please answer me. Im a beginner so i Would like some help.

  32. Reply Rebecca Jan 13,2015 9:34 pm

    Sorry my telphone is changing the words. Buur you know what i mean

  33. Reply Ryan Jan 13,2015 9:42 pm

    My neon tetra of about 4 weeks is losing his dorsal fin! I don’t know if this is fin rot or what, but please help me. Are the fish nipping? I can’t tell

  34. Reply ao Jan 20,2015 4:04 pm

    my neon tetra is sinking to the bottom and can get up but it looks REALLY hard.
    i dont know whats wrong?

  35. Reply S.R. Jan 26,2015 7:54 am

    I would like to know what kind of frozen food would you recommend feeding Neon Tetras? I have tried frozen bloodworms, but they are way too big for them to eat & most if not all of them end up at the bottom of the tank & never eaten.Also, I am concerned my fish might get parasites from the frozen food.Is this possible?Thsnks for your help!

  36. Reply Joanne Feb 5,2015 1:14 am

    I kept fish as a teenager,and had success. That was many years ago. I have a new Fluval Spec 5. There are 3 small live plants . I cycled the tank (something I never did as a successful teenage fish keeper) I tested to water (never did that either as a teen).Last night I purchased my first 5 fish- small neon tetras, from a store where my son, the saltwater tank person, has purchased many a fish.
    One was very pale when we arrived home. Everyone floated in their bag of water for about 45 minutes and then were released into the tank. the pale guy was pointing down and floating with the current. The rest of the evening the healthy looking 4 were gathered still in the back. Lost the one by morning. Came home from work and lost another 2 with a third pale and still. Only one is bright and lively. What’s going on? I checked the levels and temp over and over. No change.

  37. Reply Jay Feb 8,2015 7:53 pm

    I have a pair of cardinals,the male is very vibrant but the female barely eats and hides most of the time, I have sperated them from the community tank and he is chasing the female trying to get her to breed when he gives her a break she gulps air and her tail drops I have given them methylene blue to see if it would help. Is there any other action I should take?

  38. Reply Dennis Feb 10,2015 1:59 am

    Hi Dennis my smallest neon tetra died In front of my face

  39. Reply Conchita Feb 23,2015 6:09 am

    I set up my tank they way it was directed, this was a couple of hours ago. I had a little house in it at first but i noticed there wasn’t as much room for my two tetra fish to swim. So i took it out. The tank does have an LED light. I am wondering if that is what is causing their tank shock because they are restless at the bottom just in the same spot. I really do not want them to die. What is the best solution? Should I turn off the LED light maybe?

  40. Reply Tina Mar 5,2015 8:19 pm

    I started by 55 gallon tank in July after month of maturing, added 5 neons, 5 black tetras and 3 blood line tetras. They did fine, 6 weeks later added Angel fish and 2 small plecostamus they did fine. Two weeks ago, found plecostamus dead. My daughter felt bad for me and went to another fish store bought another plecostamus and 6 glofish, she was told by the store that they would be fine with the fish I have. I have lost all but three glofish and 3 black tetras begining a week after, one at a time, the older fish going first. I started changing out 25% of water and this didn’t seem to help. I am heartsick and don’t know what to do from here on out. How do I rebuild the tank?

  41. Reply Miss Cellany Apr 14,2015 4:29 am

    I bought 11 gold tetras over a week ago and acclimated them over 24 hours to my tank (the GH of my tank was very different to the GH of the shop water – about 10 degrees lower than the shop).

    They survived acclimation (I was expecting at least some to die) but today I found one dying and stuck to the filter intake. I took it out and put it in a bucket. It died shortly after.

    The only symptoms I could see were emaciation (they haven’t really been eating well despite me putting food in everyday), a goldenish sheen on the very top of the back, and ragged looking gill edges. The spine was slightly curved upwards as well, and the mouth was wide open during its last day and after death. It seems it had trouble “breathing” towards the end (rapid gill movements the day before it died).
    This particular fish had been hiding under the filter for a day or two before dying.

    All the fish school together at lights off but hang motionless in one spot during lights on. They have been darting around in the last day or two and one or two of them seem agitated / irritated (no flashing but they have been doing weird twitching movements as if trying to “shake something off”).

    They have no colour so it’s impossible to tell if there are colourless / white patches although some of them have transparent backs with visible spine and swim bladder and some are silver all over (individual variation or indicative of disease?).

    I’m worried it’s neon terra disease – is there any way to tell for sure? I fed them garlic in their food today and they went for it like piranhas… (much more interest in the food with the garlic in it).

    I really hope they don’t have NTD 🙁

  42. Reply Boyka Apr 14,2015 11:51 am

    My tank is 280 liters.
    And the tank mates are diskus fish.
    And when i turn off
    the lights and go to sleep by night, the next morning 1-2 or 3 neon tetras are dead.
    Help please

  43. Reply Makalani Apr 30,2015 12:11 am

    Hi Dennis-

    I have had 4 neon tetras for about 8 months. Everybody seemed to be doing pretty well. Two days ago I moved one fish, which seemed to have an enlarged body, into a separate, adjacent bowl. All 4 fish were clearly distressed about the change on the first day, but then things seemed to calm down. Today, I found all 3 of the tetras in the main tank dead against the filter. The isolated tetra appears sound. Is is possible that the stress of removing one fish killed the others? Food has not changed.

  44. Reply Denise Jun 9,2015 4:13 am

    Alot of small tetras like neons and cardinals suffocate from even minor invasions of parasites like ich and velvet before you can detect it by clogging their gills. All you do is raise the temp, cover all sides of the tank, keep the light out, treat with medication. A heavy handed dose of water conditioners that promote extra body slime will do the same quicker. Some pet stores squirt enough in the bag to dechlorinate a small lake 😒 buy the biggest fish that look like they’ve been in the store long enough to recuperate from shipping. Get at least 6.

  45. Reply Denise Jun 9,2015 4:24 am

    Jo. Your bloated one eye neon probably has a diseased or ruptured swim bladder . Especially if he’s the only one. If your fish died shortly after u buy it, freeze it and take it back. Unfortunately most are Mia over night. But a reputable dealer should take your word for it if as little as neon.

  46. Reply Denise Jun 9,2015 4:33 am

    Jo. There is a disease called, “pop eye”. It’s most common in gold fish but I’ve seen it with tropical.

  47. Reply Jake Jun 27,2015 5:00 am

    I have had 5 neon tetra for a week now, and I just introduced 6 bloodfin tetra to the same aquarium and I just lost 2 neon tetra tonight, loss of color and eyes appear to have no pupils. Is this a disease or are the bloodfins attacking the neon? I haven’t seen any actual signs of aggression between the fish. Any advice is appreciated.

  48. Reply anna Aug 1,2015 2:23 pm

    Makalani, the same thing happened to my neon Tetras, i found one on the bottom of the tank but still alive, i put it in a separate bowl, when i came back home it seemed to be doing okay. I returned it to the tank but the following morning was floating on top of the tank dead. Within two days the other three Tetras died one after the other. Am a first time fish owner and i would really like to continue keeping Tetras. Any ideas why this happened?

  49. Reply Romana Sep 17,2015 8:05 am

    Hi. I have question. About 2 weeks ago I added 4 tetras to my betta fishes 8 gallon tank. They all seem to be doing fine and I never see the betta attack them. But just the other day I found a tetra read and just this evening I found another. I tested the water level and I think the amonia is a bit high and the water is hard. I do have a filter and heater as well. I feel the other 2 are soon to pass on too, they are at the bottom of the tank,motionless. I’ve added what I have on hand, stress coat and some water conditioner to maybe help a little. So should I be concerned about my betta? He does seem a bit adgitated. Should I remove the betta temporarily or the tetras?

  50. Reply anza Sep 19,2015 7:39 pm

    I have 5 neon tetras one of them which is the smallest has recently got slight darkness in the area above its eye. Non of the other tetras have this, is it normal? I am slightly worried I don’t want to lose any of my neon tetras. Any idea what this could be?

  51. Reply Newbie Sep 25,2015 2:04 pm

    I’ve just found my neon tetra dead, he was wrapped around the filter so I assumed he was dead. I gently pushed him off and he seemed to swim of with his other neon friends, although I returned a few minutes later to see how he was getting on and he was on the bottom of the tank being nibbled so I got him out and on closer inspection he had lost an eye and looked like his tail had been nibbled.
    What do you think may be the cause, a disease, a bully in the tank or the filter killed him?? I have 8 remaining neons, 4 Molly’s, 4 guppys, a pleco, a betta, 2 bottom feeders & 6 new ones that are silver/white with neon red eyes? Thank you kindly oh and I have a 100 litres corner Aqua tank & tested water and all fine. The new fish have been in a week and a half. 😃

  52. Reply audrey Oct 21,2015 2:39 pm

    Last night all my fish were fine, but this morning one of my neon tetras color has faded, mainly the red and I can see his insides better, what would cause this and what do I do about it?

  53. Reply jesse Oct 23,2015 1:50 am

    I was just looking in my tank and noticed a couple of my tetras looked like they were not doing so hot. Like the article says, they were just kind of swimming in an odd fashion. I thought I had maybe just not noticed them doing this before but I’m glad I found this.

    I was on another site that I just stumbled across the other day and it didn’t have anything about this specifically. it was profreshwateraquarium
    I don’t know if its .org or .com since its in my history and it cuts off the website but I think it is .com, I think it must be a new site or something cuz a lot changed on it since i was there a couple days ago. interesting to read the stuff though cuz its funny sometimes.

    anyway thanks for this page cuz I think it will help with my tetras now if maybe i get them out and put them in my little 5 gallon. i just changed it over to this 20 the other day so it still has the good water in that one but probably the problem was i didn’t cycle the water good enough yet to have all the tetras in it


  54. Reply abi Nov 10,2015 2:36 pm

    Hi my names abi

    My neon tetras skin colour seems to be fading they have their red and blue stripe but it looks like it is fading slowly from the belly up .I am not sure what is wrong with them and if my other fish will be affected .Please tell me if they have neon tetra disease and what I can do .

  55. Reply abi Nov 10,2015 2:39 pm

    My neon tetras have the same condition as audrey

  56. Reply Michelle Ochoa Dec 9,2015 6:28 am

    We purchased 5 neon tetra, we put them in a shallow but medium size bowl, The bowl is brick red color, with fairy moss. The immediately began to prune the roots and made like a nest, they then slept in the nest at night, they are active, and without a filter, the are swimming and eating normal as far as I can…I took them to a ceramics exhibit, a car trip to and from the venue. They did fine. They have blended their color into the bowl, when I transferred into a pitcher to transport, I notices through the clear plastic that they were white and orange, when home, returned them to the bowl where the resumed their activity. I am hoping that the fairy moss is providing them the food and oxygen they need. I am also giving them very small bit of fish food. I will let you know how things go if anyone is interested, but what I wanted was a small water feature for the dining table, without a pump.

  57. Reply New Guy Dec 13,2015 7:24 am

    Hi. One of my neon tetras has been resting on the filter intake for almost 2 weeks. He has lost all color and has not eaten. I’m worried that he might be sick since I haven’t seen him move this whole time. I want to try to pry him off the filter w a net but am worried about injuring him. What should I do?

  58. Reply Amy Dec 14,2015 3:26 pm

    Hi, if the fish has lost a lot of color and has been resting against the filter motionlessly for almost two weeks, I hate to say this, but it’s probably dead. You should remove it immediately and check your other fish for diseases. Check for any kind of growth on their bodies such as little white spots that sometimes look like grains of sand, green or gray “slime,” and/or partially missing fins. By far, the most common fish disease is ick or ich, which appears as little white spots. Ick is very contagious and very deadly. Sometimes secondary infections such as fungal growth like fin rot (missing fins or partial missing fins) and the gray/green or white slime growth can take place during an ick infection. If your fish are free of disease, check the water quality. If the nitrates or nitrites (these are fish waste products) are too high, it can stress your fish out and kill them. If the pH is funky or the temperature is way off, it can stress the fish out and kill them as well. Tetras like water that is between 70 and 80 degrees F and slightly acidic water like 6.0. A pH from 4.0 to 7.0 should be fine. Healthy temp, pH, and nitrate/nitrite levels will help your fish fight off disease. Unhealthy levels of these will make your fish more prone to disease. If your fish have ick, treat it right away with IckGuard or MetroPlex, then worry about treating any fungal infections. If they don’t have ick or anything other type of disease, simply correct the water and watch for any diseases that might pop up over the next couple of weeks. Best of luck; hope your aquarium gets healthy again.

  59. Reply Lauren Dec 22,2015 5:42 pm

    Hi Diane! I’m having the same issue with my tetras, and was wondering if you could give me some helpful hints as to what worked and what didn’t. I have had this tank for almost a year now and can’t seem to keep any fish alive. Is there any treatments or starter kits that worked well for you and your fish? If so, please give me a buzz. Thank you so much for your time!

  60. Reply Kylie Jan 17,2016 2:14 am

    I just bought 5 neon tetras from petco and a pleco from the same tank. I added them in with my betta (they are all getting along, he has been with other fish before). On my way home, one of them died in the bag. After they were all settled in at home (I went through all nessecary steps to add to new tank) they seemed fine. Didn’t eat two of the times I fed my other fish but other than that they seemed normal. 2 days later, one died, the biggest one. A day went by and another one died after that. I now have 2 left and I don’t want them to die too 😕 have a good heater on at all times, tank is next to a space heater-water temp is an average of 74 degrees F. My tank was salted, I frequently do water changes and my other fish are healthy. Also always have the filter running. I use a pH balancer from petco also, and any water added gets treated with the tap conditioner. The tetras also have a little bit of red on their fins towards the top that I didn’t notice when I bought them and didn’t see in any other pics online. Swim pattern is normal. There is also a little red around their eyes. The one who died yesterday had a little string of waste coming out that also looked like it had red in it. Is something seriously wrong??? Is it my tank or my fault or did they just come like that maybe?? I feel so bad and i don’t want the others to die!

  61. Reply Codi Jan 26,2016 5:24 am

    I bought 3 neon tetras exactly 8 days ago, all where very active and had nice neon colours, but tonight when I went to feed them I noticed only one even tried to eat food, and the other 2 didn’t even try, they sat at the back of the tank and didn’t really move. The are duller and kinda gray, is there anything I can do for them? I’m brand new to this tank thing and the people at the pets store told me I shouldn’t even get pH strips or a thermometer, they said they’d be fine. I’m concerned about them and if anyone knows anything about what I can do that would be great! I’m definitely going to buy pellets, a thermometer, and pH strips tomorrow and will probably have to take in some dead tetras within the week for my “free refund”. I’m not so excited about this fish tank thing anymore 🙁

  62. Reply Liz Silva Jan 26,2016 2:24 pm

    Hi – we just got 4 tetra fish. We followed the instructions that came with the tank and the pet store and set up the tank a day before getting the fish. We put them in the tank inside the bag etc. They seemed fine until today one of them is twitching and hanging out by the heater. In between twitches, it floats upward for a second, then comes down when it twitches again.
    Is it dying? Is there anything I can do? Should it be removed to protect the other 3 fish?

  63. Reply Aynsley Jan 26,2016 10:09 pm

    I bought six neons for my five gallon Fluval Spec about two months, their only tankmate is a apple mystery snail. My grandpa (who had kept a small tank for many years) said he had never had much luck with them, for him they would slowly die off within a few months. For the fist month they were all fine, then I lost one, without any signs of illness or being slow that very morning. after that they would slowly die off one by one, again with no signs of any problems. Im down to two now. Am I doing something wrong? I introduced a beta just last week and there have been no deaths since then, and he doesn’t even give them a second look.

  64. Reply Shannon Jan 30,2016 5:17 pm

    My husband started a tank and spent close to a week getting the water day, he’d been told 3 days would be looking enough but we wanted to be safe because we have hard water. When we bought the fish we got them from Petco and we bought a pleco, two ghost shrimp and 3 neon tetras, we acclaimed slowly and engine did fine for days so we added a couple more neons and a couple more ghost shrimp and two red cherry shrimp. We lost a shrimp a couple days after adding more fish and a couple days later lost a neon, it basically isolated itself, got weird and turned white. We checked the pH of the water and it was kinda high, how do we lower the pH of the water safely for all the fish? We bought some kind of additive and put a drop in but didn’t want to overdo it. Everyone seems to be doing fine and we’re keeping a very close eye on them, I just don’t want any more to die. Any advice would be greatly appreciated!

  65. Reply Jicoeg Feb 6,2016 2:07 pm

    Hey, Can Neon Tetras Live in 28 – 31 celsius ?? and.. how many tetras/gallons ? i have 12.5 Gallons.. how many should i buy ?

  66. Reply Zuz Feb 10,2016 6:52 am

    Sounds like many of these fish are dying from ammonia poisoning. Please Google “aquarium nitrogen cycle” if you have not “cycled” your tank. If you are in doubt, go buy a test for ammonia and a cycle starter like “Tetra Safe Start.” If there is ammonia in the tank do a large water change (up to 80% depending on how much ammonia to bring it down to under 1ppm) and then add the Safe Start product as per directions.

    A 5 gallon tank or container is too small for a school of neon tetras.

    Don’t mess with the PH unless you know what you are doing. Most neons are tank raised and should acclimate fine to municipal water treated with a dechlorinator.

  67. Reply Matthew Feb 12,2016 2:46 am

    I set up a 37 gallon freshwater tank a few weeks ago and have been running into a few issues that have stumped two pet stores and myself. I started with 3 neon tetras, 3 black neon tetras, and some live plants. I acclimatized the fish and plants prior to release into tank and each day I found a new dead fish at the bottom of the tank or stuck to the filter. I treated the water with dechlorinator prior to adding fish, by the way. I ended up with 2 neons and one black neon tetra. I brought a water sample to be tested and was informed that it was perfect. I waited a couple weeks then got a small Cory (forgot what kind, but it is supposed to top out at 3″), a small bristle nose pleco, 5 neons, and 5 black neons. Two days later I found 2 dead neons and 2 dead black neons. Brought them back for replacement with another sample. Again the sample turned out perfect, but over the course of 3 days I had 2 of each die. A week later I added a banjo catfish and a dozen ghost shrimp to help the Cory and pleco out, but the banjo ate half the cleaning crew (shrimp) overnight, which I kinda of expected. No fish died and I thought I was good. Then I turned off the lights, read my kids a bedtime story, and noticed a black neon tetra in its death throes at the bottom of the tank. It was less than 10 minutes from lights out to dead fish and I can’t blame the banjo because it still had its head buried in the sand like an ostrich from his morning. What the heck is happening to my tank? I would have been more comfortable if my banjo was eating the fish instead of them just dying for no discernible reason. No sign of disease, heater set to 75F. Some light whitish fuzzy stuff on glass that seems harmless from everything I have read. Any ideas?

  68. Reply Matthew Feb 12,2016 2:49 am

    I’m almost at the point of waiting for the rest to die off and just buying baitfish for a bait shop; at least they are cheap to replace.

  69. Reply Ryan Feb 19,2016 4:28 pm

    You’re suppose to CYCLE the tank one month without ANY fish to get the proper bacteria etc growing in the tank.

    When you start a new tank it only needs to be treated
    for chlorine once not every time you add fish. When you get fish from a store float the bag 25 min, take half the water out and replace it with the same amount from your tank. Float it again 25 min. You can then release the fish NOT using any water from the pet store. Net them out and release into the new tank.

    There are products like Nutrafin CYCLE that promotes good bacteria almost instantly. While not the real way to do it better then not at all. I also suggest you get an ammonia and ph test kit so you can test your water. You want ammonia at 0.00 and PH varies on fish average is usually 6.5-6.7. Again it depends on the fish you have you adjust the ph accordingly.

    You’re fish are dying because your tank isn’t established. As for the pet store they really don’t care what your tank is like and would sooner give you new fish. Not look at the real issue an uncycled tank!

  70. Reply Alaina Feb 22,2016 2:18 am

    I bought a 29 Gallon tank with 4 neon tetras and 4 goldfish. Within a couple hours of have the tank 7 fish were dead. The neons were swimming upside down and then would iratically take off, and then lay upside down again and then they died. Then all of a sudden the gold fish starting. we filled it with tap water. We left them in the bag until the temperature of the tank was 76 degrees then let them out of the bag. The one goldfish that was left looks like its starting to dye. Any suggestions? We did get stuff to de chlorinate the water and they are still dying

  71. Reply Rob Feb 25,2016 3:17 am

    I wonder if my neon tetra has neon tetra disease. They dont have any white growths but the red is fading from there belly’s and the line on there back is a dark purple. I would just like some help because these are my first tetras and i would like for them to be happy.

  72. Reply Rick Disneck Mar 12,2016 11:06 pm

    My neon tetra keeps dancing when I put on beethoven, am I doing something wrong? It also bullies the fighting fish into a corner and gets all gangsta on its ass. Shouldn’t it be the other way around?

  73. Reply Mary Mar 28,2016 7:51 pm

    My cardinal tetra is not eating at all and when it reaches a certain level in the water it swims back down like there is a barrier it can’t break. The water conditions are perfect and it is living with a green neon tetra, a glowlight neon tetra, a albino cory and a zebra snail. We recently lost our neon tetra which died about 3 weeks ago. Please help me it is desperate.

  74. Reply FishMan Apr 19,2016 11:03 pm

    Hey one of my tetras died and I can’t figure out y he had good color I feed them well every day and I had him for about a year so I don’t know y he died my water is neutral the n2 n3 are 0 and he was one of my biggest tetras pls help!

  75. Reply Ashlie Apr 27,2016 4:49 am

    I had bought 5 tetras and only one lived every time I buy more they all die except the one that stayed alive from the first time what is going on I float them for a half an hour and introduce them to water slowly

  76. Reply Bev May 3,2016 12:56 pm

    My neon tetra has completely lost its colour, I also noticed that it’s tailfin was under a rock. I helped him out an there was no bleeding. He immediately hid in a plant. I think he committed suicide, recently 2 other of my tetras died but didn’t look pale or ill. What do you think?

  77. Reply Charlotte May 16,2016 8:34 pm

    I recently brought 6 neon tetras about a week ago.
    When I first added them to the tank one of the fish went and hid in the bottom corner by the plants now every time it comes out to join the others there’s 1 other tetra that seems to go for it and chases it away. They’re all eating well and swimming ok and seem to stick together apart from that one. Also the blue on it is a lot brighter than the others. This is my first time owning a tropical tank, So I’m just wondering if this is normal behaviour for neons or not? They are the only fish I have in the tank at the moment.

  78. Reply Chris Jun 14,2016 7:07 am

    I just bought a 10 gallon tank and allowed it 36 hours to filter through before I put fish in. The temperature was between 72-78 at all times. I acclimated three neon tetras and in less than 10 hours, I looked and they were dead. Any ideas on what may have happened?

  79. Reply Victoria Jul 22,2016 11:22 am

    I’m new to the fish keeping business, I bought 6 neon tetras 2 days ago, they looked like they were going well until I looked at them today when I got home from school and they were really dull in colour and only slightly swimming at the bottom of my tank. I cycled my tank for a week before adding them and tested the water and asked my local pet shop if the levels were safe they said yes so I bought the fish and now I’m sort of stressing about if they’re going to die.

  80. Reply Fish lover Jul 22,2016 4:01 pm

    I had 6 neon tetras and every day they kept dying at first it was 1 🐟 then it was 3 and today was 2.
    What happened?

  81. Reply Human Jul 25,2016 12:15 am

    My Neon Tetra is swimming upside down, swimming frantically, cant eat, I’ve seen her try, but she’s just to all over the place. I have a 10 Gallon fish tank 1 Pleco and 6 Tetras a water filter but no oxygen thingy majig. I am debating whether to buy an all purpose medicine or an oxygen thingy majig. Any opinions might help, short on cash and would like to help out my fish friend.

  82. Reply Jill Aug 10,2016 9:45 am

    Hi would be so grateful for some advice! We have 5 neon tetras have them for two months now. We also have a small rainbow shark & a bristlenose. Two days ago two of the tetras have a white lump on them! One is on one of its lips & the other one just above his eye!! What is it & what can we do to help them?

  83. Reply ankita kundu Sep 5,2016 1:53 pm

    can i put white cloud fish with neon tetra in a aquarium?? what is necesary machine??

  84. Reply Mara Sep 16,2016 3:29 am

    I found this site when I was looking for help a few months ago: It has a diagnostic tool that might be useful to queries when folks here can’t respond quickly.
    Also, for Tetra-specific disease.

  85. Reply Lauren Sep 17,2016 11:20 pm

    I have the big neon Tetras. The ones that are colored like ink,blue,purple,etc. i noticed today on my Blue neon tetra that there is a yellow/orangish lump on the top of her head. Is this some kind of tumor or is something urgent happening? A few weeks ago i noticed a tiny orange spot in the same place, Its seems to have grown! please help!!!

  86. Reply Amie Oct 17,2016 8:25 am

    I bought a beta fish at petco. It died very quickly in my new aquarium. A 2.5 filtered betta aquarium. I did everything to prevent the next one from dying. I bought freshwater instead of unchlorinating tap water, bought a heater to stay at 78 degrees. And rewashed everything. Now I went to a fish store and told me I can buy a betta and also get tetras since they are compatible. Great! I brought them home. Let them sit for an hour. Then acclimated them for 1 hour. I added few drops of the tank water into their cups and bag. 30 min later I let them in. I also avoided pouring their cup water in the tank. They seemed to enjoy it. Swam around normally. After 2 hours, things went wrong. I made sure the temp was ok and the fish before I went to sleep. But I couldn’t find one of my tetras. Finally I see him hiding in the plant deco. At first I thought he was stuck so I let him free. He quickly floated up and swam kinda funny. Then my betta grabbed him by the tail and dragged him around. I tried to break it up but it failed. Then my betta let go and he went into the filter slightly. His gills were still moving so he was alive. I thought if I could scoop him up quickly and put him back in the cup he will have a chance of survival. Sadly he got stuck in the filter and when I scooped him up he was gone. Then my other neon tetra who was just acting fine…suddenly starts floating up but still swims here and there then starts floating again. I could tell he was dying. So I scooped him up to separate him as well but when I did he was already gone. Now my betta is in there. I turned off the filter because I don’t want my betta fins getting stuck in there. He’s fine but I’m afraid something might happen overnight like last time. What do I do! Idk what is going on! Everything is perfectly fine then just goes a wall after! I can’t bear to see another fish die. I asked all the questions and made sure of all the steps I did but why is this happening. I will be devastated if my second betta dies too. I’ve got everything that isn’t necessary but can help the health of my fish. Idk what to do. Please help. My aunt just sticks her betta in a vase with two water and feeds it once a day and it survives. Why is mine not working. Btw the water is freshwater meant for fish. Made sure ph, nitrates, etc are good. The right temp. What more can I do I can’t let another fish die

  87. Reply Hannah Oct 19,2016 10:41 am

    So recently one of my Neon terras died yesterday and looked pale and sickly, I searched up what could have caused it but only saw that it could have been sick.
    So today when I came home, all my neon terras colors had faded and stuff coming out of their mouth, just like what the dead neon terra looked like, I have a betta as well and he isn’t acting the same, I worried they had the Neon terra disease and spread to all including the betta (if possible, I’m not a fish expert), I’m pretty sure their gonna die tommorw… Anyway I can prevent this or do I just let it happen (I originally had 5 terras btw and a Betta probably a year or so old)

  88. Reply kate Nov 6,2016 2:23 am

    My tetra was perfectly fine until this morning when i woke up. He looks really skinny and his scales look as if they are wasting away. He seems very fragile and wont move and is just sitting on the bottom. He is away from thebother fish in a big plastic jug now.
    What is wrong with him?

  89. Reply Heather Jan 15,2017 11:04 pm

    I have some golden tetras in my tank along with other fish. We lost one of them about 2wks ago – suddenly died. Now it looks like we may lose another…it has a swollen silver tail appeared. My platys have gone a bit discoloured too over the last few weeks as well. Is this all related or two seperate issues?

  90. Reply Kitty Jan 17,2017 9:12 pm

    Irreversible death? There’s another kind?

  91. Reply Deza Jan 30,2017 1:45 pm

    Hey.. I brought 6 neons tetras yesterday.. Did everything your meant too… water is fine.. but they are literally dropping dead… Three died over night, and one has literally died this morning… They were all healthy and brightly coloured still, so don’t understand what’s happened.?? Help…!!

  92. Reply Kayla Mar 8,2017 2:55 pm

    My sister has a one gallon tank with four tetras. She has had them for almost ten months, and they were almost babies when she got them. One has recently been having a problem not listed here. He or she’s tail end is constantly rising upward against his or her own will and forcing him or her to swim vertically all the time. Does anyone know what could be wrong?

  93. Reply Gus Pickett Mar 8,2017 10:16 pm

    My neon tetras are really boring. They are healthy and they come out to eat, but then they all go to their separate corners of the tank and don’t move again really until the next day. It’s planted with live plants and bogwood so I never see them. I think it *might* be because one of them is a bit aggressive and chases the others around, or maybe they’re just happy where they are. Who knows, but my tank looks empty most of the time. 🙁

  94. Reply Irina Mar 16,2017 7:33 am

    Hi… My neon innesi lose color overnight. Is that normal?

  95. Reply Daniel Apr 18,2017 11:21 pm

    I have 17 neon tetras that are doing great! Got ich before but just raising the water temp breaks the ich reproduction cycle, problem solved! If you treat ich with medication, it will kill ur shrimp as well as soak into u r filter.. so replace ur filter and carbon after treatment. Also some started to get fin rot, this was due to having leaves on top of sand substrate. My bushy nose place buried leaves under sand digging around.. This was messing up water quality. Now I put leaves into bucket of airiated well water, after a week I use this low ph..tannid water to do water changes. I also don’t use carbon with my filter as it takes tannids out of the water. Now my neons are healthy, have bright colors, and growing well. If kept really properly captive breed neon tetras seem to be fairly tough fish for their size. My neons also share the tank with gold tetras, albino bushy nose pleco, ghost shrimps, and s.a.. bumble bee catfish. All are doing great, hope this info helps others. Happy fish keeping everyone!

  96. Reply Trevor Apr 29,2017 12:49 pm

    Dennis you’re a terrible writer and this article is a joke. should be ashamed for allowing this to be published.
    You advice your readers to add Stress Zyme if fish they just purchased die within a couple hours? Obviously you have no clue what Stress Zyme is for, it contains live bacteria that specifically brake down organic material on the substrate. If the water isn’t mature as you say because it’s a new tank then how the hell would there be an overabundance of waste on the substrate? I think the product you were looking to recommend is called Quick Start, it contains live bacteria that help colonize the beneficial bacteria needed to break down ammonia and prevent new tank syndrome.
    Your picture of Neons are actually Cardinals, how do write an article on Neons and post a picture of the wrong fish, especially after you described their markings?
    Last but definitely not least you tell the reader to take the fish back to the pet store and ask a professional what’s wrong with it if it’s swimming in various unusual ways. That’s great advice but isn’t that the point of this article, to inform the reader why the Neon is dying? Unless the fish has visible markings showing disease or injury then the next logical answer would be poor water quality. Why would you advice the reader to take a dead fish to the pet store unless it has obvious physical signs for why it may have died? Yeah I’m sure the local pet store will love dead fish being brought in for no reason especially when most pet store employees are far from professional and less knowledge then you do Dennis.

  97. Reply Sky Jul 7,2017 8:17 pm

    I need help, 4 of my neon tetras died on the first weeek, 2 of them just vanished and three where found by the filter. I bought 7 more but I had one neon tetra that survivid from the last group of neon tetras that I bought but I notice that it was losing color, what does this mean, can it infect the other neon tetras, please help.

  98. Reply Fish Enthusiast Aug 27,2017 12:02 am

    Our neons are swimming around the bottom of the tank. They do take bouts of swimming in the middle, but most of the time they just do lazy circles in the bottom half of the tank. Is that unusual? Ours are remarkably hardy, tolerant, and just straight up troopers. They’ve never gotten sick and weathered infections that had the other fish ill and droopy, but with no reaction. At all. Just lazy circles and lines in the bottom-middle half of the tank, and foodnabbing. They always are the first to get at the food when fed, even if they were only fed about an hour ago, and seem fine enough. Oh, and we’ve had them for about a year.

  99. Reply KRISS Sep 6,2017 1:56 pm

    Please help me out my neon tetra are dying when I buyed it they were in a group and then later they rome lonely and die please give me a solution and i do have a loys of fish in the same tank ..please help me out

  100. Reply Katie Sep 18,2017 2:05 pm

    I have two neon tetras that have one spot of ich on each of them. They are in a 20 gallon tank with a pleco and 4 other neons that look and act fine. How do I treat properly in that tank and how do I raise the water temperature? I have a heater but I don’t know how to raise the temp with it. Also, do I turn the filer off for 3 weeks while the treatment is in progress?

  101. Reply Chelsea Nov 25,2017 8:40 pm

    Hello All,
    I currently have my 4neon tetras and one platy in my 10gallon (sadly my other mama platy recently passed away). I’ve had them now about 2.5 years and have never had an issue other than wonderful black mold growing in there and these damn snails that no matter what I do keep coming back. I keep it as clean as possible from the black mold but recently one of my tetras seems to be sinking a bit while swimming. I’ve never nursed a tetra but have nursed my platies… Should I put him in a hospital tank and use the epsom or will he be too freaked alone? Everyone else looks just fine and healthy. Thank you!

  102. Reply Chloe Feb 8,2018 10:11 am

    Hey my neon tetra is lost his colour and is super skinny and small he hides then he’ll come to the front and he is not swimming with the other tetras do you know what is wrong with him

  103. Reply Rachel Mar 16,2018 6:26 pm

    I overfed my new classroom Glofish Tetra. I am purchasing a gravel vacuum this weekend, but won’t be back at school to clean the old food until Monday morning. The tank isn’t very cloudy, but does have a slight smell. Will my fish die over the weekend?

  104. Reply Michael Bobee Mar 24,2018 3:31 pm

    I just purchased two neon tetras to replace one that had died several weeks ago. I had two in the tank at that time. When I added two to the group, one was isolated and died in a week. It seemed like the group accepted one and isolated the one that eventually died. Was this social or a pre-existing condition? Thank you.

  105. Reply Steve May 4,2018 3:10 am

    I bought two neon tetras recently, and when I got homeless them in the bag to get used to the water. After fifteen minutes, I let them I the water. They looked happy, active and playful with each other. But the next day, in the morning I saw they were sticking to the filter and dead. Should I get more tetras? Why did they die?

  106. Reply Steve May 4,2018 3:22 am

    I bought 2 tetras and a guppy. After leaving the fish in the bag for 15 minutes, I let them in the water. The tetras looked active and playful, and the guppy stood restless and didn’t make much fast moves. The nest day, I found them stuck to the filter… dead.
    Why did they die? Should I buy more tetras?

    • Reply Chutney Aug 25,2018 5:08 am

      Did you cycle the tank before hand? How you ever had other fish before? Did you check the ph and recommended temperature? These are all important to keeping your tetras living, and cleaning the tank is too.

  107. Reply Heidi Jun 28,2018 10:55 pm

    I just bought 15 neon tetras a week ago and put them in a 17 gallon tank. Yesterday I saw that one of them was missing part of their fin and they were having trouble swimming. This morning I went to feed them and I found the one that was missing part of its tail dead. I thought it was just an accident, like it got caught in the filter or something. In the afternoon I went to look at the fish again and found two more dead. At night I checked again and another one was dead. I don’t want any other neons dying. What should I do?

  108. Reply Chutney Aug 25,2018 5:07 am

    One of my tetras died after 6 months. My betta fish in the tank 1 month before developed fin rot. The tetra was colorless and I was keeping a close eye on it and before I knew it the fish was dead. Could this link up with the unknown diesease. The fish didn’t seem to be eating either. I have 4 other tetras and a betta fish in a nine gallon tank. I took out the dead fish as soon as I found it. I did a 50 percent water change and went ahead and put some aqua safe in as you do with every time you clean the tank and do a water change. Are my other fish in danger and how do you tell if tetra’s have fin rot? The rest of my fish are orange but one tetra is a little less than the rest. Should I take that one out and nurse it? Is it safe to keep the betta fish with the tetras?

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