Best Heaters for Fish Aquariums

If you have a tropical freshwater or saltwater aquarium then you need to regulate the temperature and keep it maintained with a heater.

Buying a heater might seem straight forward, just find whatever heater they have shelved at the pet store. But in my opinion my fish are valuable to me and I wouldn’t trust their life to just any device. Here is the heaters I feel confident in recommending.

There are 2 different heaters I think you should have depending if you have a canister filter or not. If you don’t have a canister filter then I would recommend the Eheim Jager Heater (Amazon link). If you do have an external canister filter then the ISTA In-Line External Heater (Amazon link) is going to be great.

When I recommend filters I think people should try and go with a canister filter in most cases, and this gives you the opportunity to use an in-line heater.

My heater recommendations are based on the fact that they work well, but also mainly because they are the safest in my experience. Heaters have been known to malfunction and overheat, which has caused havoc on some people’s aquariums in the past. Yikes

In-line external heaters seem to work best in avoiding this issue. However if you need to use a submersible heater, which is perfectly fine, then I would go with the Eheim Jager, as it has a great track record. Even if you aren’t using it, having one on hand just in case as a backup heat source is a really good idea since they are pretty cheap.

Eheim Jager submersible heater

When you are sticking a heater directly in the tank in the water, you want to be sure it’s going to be as safe as possible.

In the fish keeping world there is a buzz among the hobbyist that the Eheim Jager has been the most faithful, with the least amount of issues to arise from it.

It’s fully submersible so you can stick it down near the bottom of the tank and horizontally for maximum heating coverage.

And being a submersible heater it’s still very affordable. Just check what the prices are on Amazon, and see what sizes are available for the Eheim Jager.

Another great option you could try out is the Hygger Submersible, especially if you have a saltwater tank as the titanium tube is anticorrosive, and the controller is external which you might prefer over the Jager.

ISTA in-line external heater

As I said above I generally recommend people to use a canister filter for their aquarium filtration. If you are using a canister filter then you have the option to use an external heater with it.

It’s called an in-line heater because it will connect to your canister filter. The water flows through the heater during the filtration process, then an output hose will push all that clean and heated water back into the aquarium.

You can see pictures of it and a diagram showing how it works here ISTA price and specs on Amazon.

A canister filter is such an amazing piece of equipment to clean your water and circulate it. If all you have used before is some Hang on the Back type filters, then switching to a canister filter would be a game changer for you.

The canister filter moves the water with a lot more power creating a better flow in your fish tank. Add your heater to that water flow and you are going to get a much more stable and consistent heat through out your entire aquarium.

Also with the in-line external heaters it is not sitting inside the tank submerged under the water. This means that a malfunction usually isn’t as costly if something does go wrong. People have had a lot more luck using an external heater because of this.

Another external heater I would recommend is the Hydor In-Line Heater, especially if you decide to go with the Hydor Canister Filter, with this combo setup.. pheww, that would be a setup to be proud of.