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Do You Need a Heater in a Tropical Fish Tank?

The quick answer is yes you must have an aquarium heater in a Tropical fish tank. Tropical fish require heated water as that is how their natural environments are. There are some aquarium fish that do not require heated tanks so technically you can’t really call them Tropical fish.

That is how you can determine if a freshwater fish is tropical or not. If the fish requires heat then call it Tropical if it does not require heat then call it a freshwater fish.


What is the Purpose of a Heater in a Fish Tank?

The main purpose would be to provide your tank inhabitant with some heated water so they can survive.

What Temperature Does a Fish Tank Need to Be?

How warm should a tropical fish tank be you ask? The inner temperature range should be between 75 to 80 degrees Fahrenheit. Some fish depending on where they originate from might require a bit lower or even a bit higher temp which means the full temperature range is actually approximately 71 to 86 degrees Fahrenheit.

The safest range though is the 75 to 80 temps for Tropical fish. As the temperature gets lower you will find your fish being more lethargic. If you see this, make sure to turn the temperature up a degree.  These water temperatures apply to saltwater fish as well even though this specific article is based on the needs of freshwater fish.


What Fish Need a Heater?

It is probably easier to tell you which fish do not require a heater as there are far less of them.

Aquarium fish that do not require a heater are Betta (or fighting fish), Goldfish, wild guppies (not fancy guppies), white cloud minnows, blind cave tetras, clown loach and Zebra Danios are the more common pet store species or fish that will not require a heater.

This is not to say that these fish can survive in freezing cold water. Room temperature is a good temp for these cold water fish.

What Different Types of Aquarium Heaters are Available?

**Check out this submersible heater over on Amazon. You won’t go wrong with this one. **

The most common and the most likely choices available to you at your local pet store will be the hanging or the submersible or immersion heaters. There are other choices available such as under gravel or substrate heating (substrate heating can help with live plant growth), heating mats for under the aquarium and if you have a sump with your tank you can put the heater there.

A less common heater but still an option is an in filter heater where the heater is in the filtration system filtering and heating at the same time.

Something to note is that all aquarium heaters should have a built in thermostat so you can set the temperature and when the water reaches the desired temp the unit shuts off. When the water temperature drops below the set temperature on the thermostat the unit will start heating again.

If the water heater you are considering does not have a thermostat then consider purchasing a different model. I don’t even know if you can purchase them without a thermostat it is just something to be aware of.

  • Hanging Heaters

    • Hanging water heaters are a great option and will be the most economical choice for you. If money is an issue, then go with this style. There is nothing wrong with starting out using a hanging water heater for the tank.
    • These heaters usually have suction cups so the heating tube can be stuck to the side of the tank without dropping in. the temp control on most models will be at the top so you can adjust the temp while the rest of the heater is under water.
  • Submersible Heaters

    • Submersibles are nice to own and will cost you a bit more than a hanging heater. submersible aquarium heaterThe reason is obvious because the heater must be air tight so no water can get inside. If water got inside the heater your fish could be electrocuted. The heater would be fried and most likely you will blow a breaker in your home. If you can afford a submersible heater get one.
    • When placing a submersible heater in the tank make sure to install it lower and closer to the bottom of the aquarium as well as placing the unit horizontally so the heat distributes as evenly and flows upwards easily. If you placed it up high on the glass then the flow of the tank has to work harder to get the warmer heated water pushed down to the bottom.


Something else you will want to consider is a separate thermometer to be placed on the opposite side of your tank to ensure the heated water is being spread around evenly. This is a great way to detect a faulty heater.


What is the Best Aquarium Heater?

What is the best heater is a really good question. The answer is very simple. The best water heater is simply the heater that you can afford and its placement works for the aquarium.

I highly recommend though that you spend as much as you can afford on a heater. You want to select one that does the job required without over heating or burning out very quickly.

You will get what you pay for with aquarium heating. You want to make sure you do not cause your fish undue stress with extreme fluctuations of heat and cool. A better heater will ensure the waters temperature stays as consistent and accurate as possible.

Your Fish and Heating Requirements

Make sure that when you are selecting inhabitants for the tank that you consider the water temperatures that the fish you want to own will thrive in. All your fish should require approximately the same temps for survival. Most freshwater Tropical fish are fairly close in temp requirements however you should still do your research.

Do not purchase fish that are on opposite sides of the temperature range as what will happen is you will have some happy healthy fish and some unhealthy unhappy fish that will slowly die.

Final Notes on Aquarium Heaters

Buying a heater really isn’t that big of a deal these days as the packaging usually tells you what size of a tank the heater is rated for. Always get a heater that is at the top range of your tank size and not one that might do the trick and is always running.

This will eventually burn out the heater and then you are off to the pet store again spending more money. Remember that you will have to plug in the heater so consider that when going to place it in the tank.

If you want to find out what Heaters I recommend you buy as a new aquarium enthusiast then I suggest that you please check out my Recommended Aquarium Gear Page.  (under construction)

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