Do Betta Fish Need A Heater?

Do Betta Fish Need a Heater?

If you have a betta fish, one of the questions you should ask yourself is if your betta need a heater.
The short answer is most likely YES!
Your betta fish need a heater depending on the country you live, where you put the betta tank and in general on the outside temperature of your tank location.


We live in a temperature controlled world. Our home, workplace, stores we shop at and even our car is automatically heated and cooled. If you feel cold, turn up the thermostat. If it feels too warm, turn on the air conditioning. But what about your betta?
The fish lives in the same living space as you. Many betta keepers assume if they feel comfortable their betta feels the same way. But this simply isn’t true.

The fact is, water temperature is a life or death issue for bettas.

When it comes to temperature and biology, bettas are very different from humans and other pets like cats and dogs. Here’s why.

Fish biology and water temperature


Birds and mammals, like dogs, mice, cats and humans are “warm-blooded.” That means that they can make their own body heat even when it is cold. They can also cool themselves if it gets too hot.
To cool down, warm-blooded animals move to a cooler location. Dogs and cats have sweat glands on their feet. Dogs pant to lose heat by water evaporation. Humans sweat. Warm-blooded animals maintain a very stable internal body temperature. In fact, most of the food they consume goes to generate heat, so the body continues to function.

But fish are different! They’re classified as “cold blooded.”

This does not mean their blood is cold. Cold blooded means they can’t control their internal body temperature.
Your fish are at the mercy of the surrounding water temperature. Fish in the wild can swim to a different location to maintain their optimum internal temperature.
If the water continues to cool down, their metabolism slows to a hibernation state. In fact, all aquatic life is regulated by water temperature.
Maintaining a stable water temperature is essential to keeping your betta healthy and beautiful.
But what kind of water temperature do bettas like?

The betta’s natural habitat


Bettas are native to Thailand, Cambodia and Malaysia.
Their natural habitats are shallow ponds and rice paddy fields with plenty of plant cover.
The sun beats down onto the water all day long.

The average water temperature during breeding season is very warm, 86°F (30°C). The ideal water temperature for nest building and spawning seems to be around 80°F (27.7°C).

It’s clear bettas thrive in warm, tropical conditions. This tropical climate is also where commercial breeding and farming of bettas for the aquarium trade occurs. Thousands of bettas are bred and raised every year under these warm water conditions.
The bettas are bread and raised in small jars. Water is changed every day or so. But the key is a stable temperature provided by the tropical location.
It’s one of the most important factors for keeping the fish in top condition and free of disease problems.
Betta breeders in cooler climates have to be very careful to provide the adults and delicate fry with warm conditions to ensure growth and survival of the baby fish.
A dip in water temperature could spell disaster for the little fish!

Low temperature and bettas


When tropical fish, like bettas, are kept in cool water, several things happen.
First, their metabolism slows down. Remember, they are cold blooded.
The cool water shuts down their growth rate and color development. Their body can’t repair damaged fins and replace old cells.

Even worse, their immune system ceases to work properly. The immune system is responsible for fighting off stress and disease problems.
Betta aquariums, no matter how well-cared for, contain microbes that could cause fish disease problems under the right conditions.
When the betta’s immune system is compromised, the fish is susceptible to bacteria, fungus and parasite attack.
Normally the immune system can fight off these pathogens. But when the temperature is low, the weakened fish will get sick.

Low water temperature also affects the development of betta eggs and growth of the fry.
Low water temperature reduces the survival rate of young bettas. Male bettas protect the floating bubble nest. If they are sluggish the eggs and fry will be eaten by predator fish.

Room temperature and betta aquariums


Small desk top aquariums are popular in today’s homes and office spaces.
The small size makes them easy to place just about anywhere in a room. But there is a problem with nearly all betta aquariums. They’re marketed as an easy “hands off” aquarium. Just fill it water and a drop in a betta.
Filtration is minimal but that is not as bad as not having a heater! Almost no betta tank kit includes a small heater or mentions the need for one. The aquarium kits are often displayed in the fish shop near a shelf of tiny cups, each containing a betta.
The novice does not know any better and follows the instructions that came with the aquarium.
Without a heater, the water in the aquarium will always be too low.

Since bettas are tropical fish, they need a water temperature of 75-80°F (24-27.7°C).

How many homes or offices operate at a similar stable tropical temperature?
The truth is, many homes and offices have variable room temperatures. HVAC systems regulate the temperature to minimize energy costs. When people are not in the rooms, temperature is often set too much lower levels.

Symptoms of low water temperature


When a betta aquarium is subjected to cool or fluctuating temperatures, bettas will show several symptoms.
At first the fish will be quite lively, swimming around the tank and showing off his fins. But over time the fish will become sluggish.
Chilled bettas often sit motionless on the bottom of the tank. When they do stir, fins are often clamped. Excitement about feeding will also diminish. Remember, cool water slows down all life functions. The fact is, the betta is suffering a slow death. In some cases, a disease will attack the fish. The fins may develop a cottony fungal growth. Split fins or ulcers are caused by bacterial infections.
External parasites attack the skin and fins. Medication won’t help because the fish is living in a harmful environment. It can’t recover.
Other times the fish will simply die with not outward symptoms. The uninformed aquarist usually assumes the fish was “old” and died naturally.
What do they do next? Go to the fish shop and purchase another betta. Without a heater the cycle begins again.
Eventually many betta aquarists give up, thinking bettas are too hard to care for.

Aquarium heaters for the betta aquarium


Fortunately, it is possible to add a heater to a betta aquarium. If you’ve got a 5 gallon tank or larger there are plenty of submersible aquarium heaters to choose from.
But what about the smaller betta aquariums.
Regular sized aquarium heaters are often too tall to fit into the tank. Others take up a lot of space. The good news is there are special submersible heaters made just for betta aquariums.
Your betta aquarium kit most likely did not come with a heater. Here are a few heaters that are made especially for smaller aquariums.

The Tetra HT Submersible Heater (check it out on Amazon) fits pretty well small tanks. It has a pre-set thermostat and will keep your tank at a toasty 78° to 80°F (25.5-27.7°C).

The Cobalt Aquatics MINI-Therm compact 5-watt submersible heaters are made for tanks up to 1.2-gallon tanks (check it out on Amazon). The small size won’t detract from your tank’s beauty.

The Aqueon Flat Submersible Heater is only about one inch long, perfect for a betta aquarium. (check it out on Amazon).

All these heaters are plug and play. You don’t have to set a thermostat. The heater will automatically maintain the ideal water temperature for your betta.
Installation is easy too. Just press the suction cup heater mount to the tank’s glass and plug it in!

A word on aquarium location

It may be tempting to place your betta aquarium near a bright window. The faulty thinking is the warm sunlight will keep the water at the right temperature.
The truth is the water could overnheat if the tank is in direct sunlight for too long.
In most cases, however, natural light won’t warm the tank.
Then there is the issue of HVAC temperature swings. A blast of cold air conditioning will chill the betta’s water.
An aquarium light won’t properly heat the water, even if it is on 24 hours a day. This is chronic stress factor for bettas kept in tanks without heaters.
There just isn’t a way to stabilize the water temperature without an aquarium heater.
Check out our article on where to place the aquarium at home for more suggestions.

Final thoughts

It’s important to provide for the welfare of your pets. Bettas are no exception.
Given a stable water temperature, your betta will live a long and happy life.
The fish will develop brilliant coloration and beautiful fins. Instead of sitting on the bottom of the tank, your betta will swim gracefully and show off his beautiful fins when you approach the aquarium. He’ll be more eager to feed too.
The likelihood of disease outbreaks will be minimized also. If your betta aquarium did not come with a heater, you have plenty to choose from.
You’ll notice an immediate improvement in your betta’s health and personality.

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Do Betta Fish Need a Heater?