Do Betta Fish Need a Heater?

Do Betta Fish Need a Heater?

Many different items are needed to keep betta fish healthy, and these range from having a tank to having a filter. I’m sure we’ve all seen pictures of betta tanks that don’t seem to have any heaters. Some of these are really well put together, decorated with a lavish aquascape of plants. So, do bettas really need a heater?

The answer is yes, bettas do need a heater. If you attempt to keep a betta without a heater, it will not live nearly as long and could die as a direct result of your decision. Before you reject this idea by thinking about that betta you had as a kid, try and remember how long it lived. If it didn’t reach at least its fourth birthday, it is unlikely that it died of causes unrelated to its care.

In this article, we will discuss tropical fish, metabolism, bloat, excessive heat and farms, and resistance to disease.


Betta fish are tropical fish, which means they need to live in tropical temperatures. Temperate fish are not overly demanding in terms of temperature and can survive a wide range, while cold water fish cannot survive warm water.

One of the main reasons that you do not see a betta fish pond is due to the inability to keep a pond heated cheaply. Bettas have to live in water that is between 78- and 82-degrees Fahrenheit. Tropical and cold-water fish are very sensitive to water temperature.

Temperate fish include fish such as goldfish, who will act the same in water from 50 to 85 degrees. You will not notice any listlessness or any extra illnesses, and most don’t show an overly increased or decreased appetite either.

However, if you attempt to keep a true cold-water fish at tropical temperatures, or temperatures above their range, anywhere from 40-60, they will die. You may notice some listlessness or excessive breathing, but there will not be much warning before they pass.

The same goes for bettas kept in water that is too cold. If they a live in the low 70’s, you will notice your fish becoming very lethargic and your little friend may lose interest in his or her food. If you keep your fish in the 60’s, you fish will hardly move and may pass in a few days.

One of the ways to euthanize tropical fish is putting them in progressively colder water. Most accomplish this by putting them in a freezer or fridge where the water will lose its heat. Others simply dunk them in ice water, which will shock the fish, but it will die very rapidly.


Betta fish are extremely hardy and adaptable fish. They can live in practically any pH that comes out of the tap, from 5.5 to 8.5. They can also live in essentially any water hardness that comes out of your tap as well, even though they come from soft water areas.

So why can’t they adapt to a different temperature?

There are very few fish that are capable of adapting to temperatures out of their temperature range, and those that can are typically warm-blooded fish. Betta fish are cold blooded fish, which means their metabolism and bodily functions are dependent on the temperature of the water around them.

If they are kept at the incorrect water temperature, their body will not be able to function properly. The metabolism and immune system cannot function at full capacity when they are kept at both too high and too low of a temperature.

Keeping your fish at too high of a temperature is not as dangerous as keeping them at too low of a temperature. If the temperature is too high, it speeds up the metabolism and impacts the immune system negatively, but many aquarium diseases and parasites cannot reproduce at high temperatures anyway.

The main issue with too high of a temperature is that your fish will not live as long. Since their metabolism is being sped up, the aging process is also speeding up. While it does not cause as much pain to your fish as cold temperatures, they are still more open to getting sick.


Bloat is a common issue in bettas, but it is most often caused by keeping a betta at a low temperature. While bloat can have many causes, ranging from impaction to a tumor, the primary cause is constipation, which is luckily easy to treat.

Since the temperature directly impacts the metabolism, if the metabolism is moving too slowly because of a low temperature, the betta is likely to become constipated. Feeding pellets that expand significantly in water can also lead to constipation.

The first step to treating constipation is to stop feeding your fish for three days. At the end of the three days, you should feed some frozen daphnia to your betta for breakfast and dinner, no other meals.

If you do not have access to frozen daphnia, you can feed part of a deshelled and blanched pea. Both of these foods act as laxatives for bettas, so they will help get things moving in there. If this method fails, feed your fish pellets/flakes for the next two days, but make the meals slightly less than normal.

Excessive Heat and Farms

Most of the very high quality and expensive bettas come from Thailand and the Philippines. The majority of breeders there are very poor, as fish do not sell for as much locally and it is difficult to make a living. So how do they raise such quality bettas?

The short answer is that they do not have to pay for utilities for bettas. Most of them are bred outside without heaters and many farms do not have any pumps for the ponds and aquariums. However, the heaters are not necessary for these bettas.

The outdoor temperatures for these tropical regions are normally perfect for bettas. Sometimes the temperature is too high for them, but as previously stated, the high temperatures are not as dangerous as the low temperatures.

These high temperatures raise the bettas’ metabolisms, which allows them to grow faster than bettas raised between 78-82 degrees. However, there is a downside to this; the bettas will need a lot more food and will produce a lot more waste.

Since these bettas are typically shipped out of the country, they will not have super warm water during shipping. Heat packs do keep them warm, but at the farms, the water may be as high as 95 degrees. During shipping, the temperature will drop, so they will be ready for your cooler water and will be able to adjust to those temperatures quickly.

Resistance to Disease

The best way to help your betta fish combat disease is to keep it at the appropriate temperature. Unfortunately, some diseases also prefer temperatures in the high 70’s and low 80’s, so to treat some pathogens, you may have to raise your betta’s temperature.

For example, Ich is often treated by raising the temperature to 84 or higher and adding salt. However, some bettas are extremely sensitive to salt, so normal Ich medications usually have better results for treating Ich in bettas.

In fact, many aquatic bacteria and parasites are unable to reproduce at high temperatures. This does create some issues on farms kept at high temperatures, though perhaps not for the reason that you may think.

The main issue with this is that the bettas on farms that have very high temperatures often do not get sick at all. This is a major plus for the breeders, as they don’t have to spend money on medications and have more stock to sell.

However, this does create an issue for you and other buyers. While you won’t be getting a betta that is initially sick, the betta will not have any defenses or immunities to diseases in your tap water or brought in by other fish.

It is best to keep these bettas out of community aquariums, at least for the first few months, as they need to build up their immune systems first by getting used to pathogens in your tap water.

In conclusion, betta fish are tropical fish and require a heater to maintain stable internal conditions. Keeping your fish at too low or too high of a temperature leaves it open to disease but keeping it at too low of a temperature is much more damaging.

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