6 Best Aquarium Heaters For Your Fish Tank 10

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Aquarium heaters are essential equipment for your freshwater and saltwater aquariums. The rule of thumb is, the ratio between heater wattage and aquarium size should be about 3 to 5 watts for each gallon to keep your fish happy and healthy.

So let’s say, for example, a 50-watt heater will heat properly for an aquarium with about 10 to 15 gallons. It’s a known fact that some aquarium heaters work better than others depending on the aquarium size. So, today we’ll take a look at what makes a good aquarium heater and some of my recommendations.

Best Aquarium Heaters for Large Aquariums

For those fish lovers who just can’t get enough of those aquatic friends, and choose to own a large aquarium, here is what to look out for in heaters.

  • Choose a heater with a large wattage, usually about 300-watts or more since the tank would hold a lot of water, ranging from 50 to 75 gallons.
  • The reliability of the heater, the last thing you want is to over (or under) heat the water and make the fish uncomfortable.
  • With a large tank, consider using two smaller heaters. That way the heat will be evenly distributed to your fish community, as you can place them in opposite ends of the tank.
  • Having two smaller heaters is also good, when one fails at least you still have one heater to keep your fish warm until you can get a replacement.

Recommended heaters for Large Aquariums

1. The Hydor Theo Aquarium Heater (300 watt)


Hydor Theo 300w

The Hydor Theo 300W Heater is a fully submersible heater. It’s known for it’s durability, so it can be counted on to last a very long time.

  • The Hydor is shock resistant having a PTC heating element, and a shatterproof glass tube, a durable choice for your aquarium.
  • Suction cups able it to freely position in your aquarium.
  • Patented PTC heating system provides for a self-limiting system, guarantees safety in case of dry running.
  • The Hydor has a temperature range of 70-97 degrees Fahrenheit.



AquaTop GH-300

2. AquaTopModel GH-300 Submersible Heater

The Aquatop Aquarium Glass Submersible Heater, 300-Watt  helps to maintain a constant and stable temperature.

This heater being fully submersible offers up a simple and easy installation with the use of suction cups, and can handle aquariums up to 75 gallons.

  • 300 Watts
  • Can be used in fresh water and salt water tanks.
  • Insulated glass construction of the highest of quality.



ViaAqua Titanium

3. ViaAqua Titanium Heater (300 Watts)

The ViaAqua Titanium Aquarium Heater, 300-Watt, is one of the latest versions of ViaAqua heaters. It features LCD temperature readout, a high-tech way to keep an eye on your tank.

  • Titanium heating element
  • Adjustable temperature setting
  • Fully submersible



Best Aquarium Heaters for Small Aquariums

If you’re more of a casual fish fan, then you’d probably have a smaller aquarium – less fish but hey it’s not how many you have it’s how you take care of them. One way of taking care of them is choosing the right heater. Here are some things to look for:

  • Choose a heater with wattage of 25 to 75 watts.
  • Durable and long lasting, to avoid replacing it often.
  • Have an extra heater just in case; with a small tank using two heaters is not that practical.

Recommended Heaters For Small Aquariums

1. Marina 17W Mini Heater


Marina 17W Mini Heater

The Marina 17W Mini Heater, with a name like that what could possibly go wrong? It is simple and easy to set up and ideal for use in your glass or plastic tanks.

The Marina Heater is a one piece unit and unbreakable.

  • Easy to use and reliable, great for you starting out on your aquarium journey.
  • Turns any tank into a tropical tank. Can be used for glass or plastic tanks.
  • Used for tanks around 14 liters (3 gallons).


2. Fluval EDGE 25w Heater

Fluval 25w Heater

Fluval 25w Heater

The Fluval Edge 25W Compact Heater is an automatic, submersible heater for use in your indoor aquariums, great for your tanks that accent the room.

Simple and easy to use – with just small adjustments you can preset it to reach and maintain a temperature of 78F.

  • Unlike traditional glass sleeve heaters that will crack or break, this bad boy has and exterior made of tough polymer, strong and durable.
  • The heater is ideal for tanks up to 6.6 gallons (25 L) and can be used in fresh or saltwater tanks.
  • Easy to use and reliable.

3. Hydor Aquarium MINI HEATER

Hydor Mini Heater

Hydor Mini Heater

The Hydor MINI HEATER 15W is a  small heater for desktop aquariums that will safely increase water temperature a few degrees.

It is simple and easy to conceal in your miniature tanks.

  • 7.5 watts for 2-5 gallon tanks (10-25 L).
  • Completely submersible.




Share Your Thoughts

For anyone that owns an aquarium, it is important to consider using the ideal heater in order to ensure that your fish remain happy and healthy.

Remember, it should be durable and reliable so you can simply worry about enjoying your pet fish!

If you have more tips or recommendations for aquarium heaters, please share your thoughts 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.

10 thoughts on “6 Best Aquarium Heaters For Your Fish Tank

  1. Reply Prakash Feb 7,2014 8:23 am

    Hi, Liked this article very much and thanks for recommending those heaters. However it would be nice if you define your idea of large aquariums. How much size (in inches) or water capacity holding (in gallons), is large according to you.

  2. Reply chris Oct 18,2014 12:41 am

    Surprised eheim didn’t make this list. I’ve used everything they make. Never. Ever. Never had a problem with them. And you can always adjust the dial to recalibrate them.

    Once I had a 240g tank spring a leak in my garage . when I found it, my street was flooded of course lol. My house wasn’t luckily. But in the tank, my heater was baking red. My sump pump was on a safety low water switch but my heater wasn’t.

    If you haven’t guessed where I’m going with this – the eheim heater made it through the baking (not submerged). Didn’t even phase the calibration. That tank was empty for at least 8hrs. That heater is still going strong 3yrs later 🙂

  3. Reply DSTOP Nov 11,2014 8:50 pm

    Just wondering why there is no mention of the EHEIM Jager heater

  4. Reply Joseph Nov 17,2014 5:46 pm

    I could not disagree more on your selections. Not a single one of them is better the Eheiem Ebo Jager or Hagen Fluval. Ebo Jager is by far the best heater that most people can afford, hands down. Funny hos these Chinese companies come out of nowhere, end up on eBay, then people think because they flooded the market that makes them good. No way I would put these on my reef or freshwater tanks.

  5. Reply Holly Nov 19,2014 8:59 am

    For Chris, DSTOP, and Joseph, I have a relatively new 75 gallon aquarium and an older eheim heater. Don’t know what the wattage is, but it seemed to be staying on a lot and when I checked the temperature, the dial had moved up to 82 degrees–and I didn’t change it, so I don’t know what’s causing the slide upward. I want to replace the heater, and read that it can be a good idea to get two smaller heaters. Would that mean that I could get two Eheim heaters of 150 watts each instead of one at 300?

  6. Reply Randy Dec 10,2014 6:02 pm

    I like the aqueon pro 250. I been using one in my 90 gallon for last 4 years with out failure. I have had other heaters of different brands and they never seem to last. Maybe I just been lucky but I use them in all my aquariums now without a problem.

  7. Reply AJ May 3,2017 5:47 pm

    I disagree with all the heaters suggested. All have dismal ratings on amazon.

  8. Reply Chris Aug 14,2017 3:17 pm

    At what point did we go for “fully submersible” exclusively? Personally I have zero faith. What happened to simply being able to clip it on the back of the aquarium? Are you supposed to bury these things in the gravel? Almost all of these prevent you, by design from using it as an inline heater. Industry trends, fashion changes… I get it. So if it shorts, explodes etc then what? They’re going to maybe give you a replacement… maybe… they won’t cover your fish. All suction cups break down over time. Nothing physically is able to hold it out of the water? A separate controller is just an additional point of failure. We’re putting this near an aquarium, we all splash water around, spills happen. Let me guess the controller isn’t waterproof & the first drop voids the warranty? If they can’t even ship one out without breaking them I seriously question their ability to do anything as complicated as “designing” something electrical.

  9. Reply Adrian Feb 15,2018 1:15 am

    I couldn’t disagree more about the Hydor for small aquariums… the purpose of a heater is to control the temperature. If its only functions are ON(plugged in) or OFF(not plugged in), how can you modulate the temperature?

    I got one for my 3 gallon desktop betta tank. I keep my apartment at 70. I put the Hydor in the tank, and the temp in there went from 70 to a whopping 71. Useless junk teasing people into thinking they’ve done something for their fish.

  10. Reply duncan Jun 28,2018 6:55 pm

    it bothers me how it says a range of size for large tanks but not for small tanks

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