Do Betta Fish Need A Heater?

Betta fish are a gorgeous, tropical fish that are common in fishkeeping. When building a tank for a new betta fish, you may wonder what equipment you need to give your fish a good life. A heater is a piece of equipment that isn’t necessary to all fish, so you may wonder if betta fish need a heater.

The answer is yes, betta fish need a heater in their tank—and here’s why.

Betta Fish Water Parameters

Betta fish are tropical fish, originating from shallow bodies of water in Thailand and nearby countries of Asia. In their natural environment, the outside temperatures range from 86 – 104 degrees Fahrenheit, and the water temperature stays between 75 – 80 degrees Fahrenheit. 

In order to keep your betta fish healthy, it’s strongly recommended to maintain the betta tank water temperature at 75 – 80 degrees Fahrenheit. 

Can Betta Fish Live in Cold Water?

Betta fish can’t live in cold water because they are tropical fish. Their bodies aren’t built for cold temperatures and they can become sick in water that is kept too cold. Water temperatures below 74 degrees Fahrenheit are too cold and can impact your betta’s health.

What Happens if the Betta’s Water Is Too Cold?

If a betta’s water is too cold, the betta will become lethargic and risk death. In cold water, a betta fish’s metabolism will slow down and it’ll lose the ability to repair its fins and replace old cells.

Its immune system will also weaken, and the betta will no longer be able to fight illnesses. Cold temperatures are a danger to your betta fish’s health and should be avoided at all costs. 

Temperature Shock

Temperature shock is a reaction in betta fish to drastic changes in temperature. Because fish are cold blooded animals, their body temperature is regulated only by their surrounding environment. When there’s a rapid change in water temperature, it causes confusion and stress. 

Temperature shock is possible not only in cold water changes, but also in hot water changes.

When a betta fish experiences temperature shock, they begin to breathe rapidly because their body has difficulty moving oxygen. They may swim erratically, or stop swimming altogether. 

To avoid this issue, it’s important that you never change the water temperature too drastically or too quickly. Gradual changes to water temperature is key. 

Benefits of Betta Fish Tank Heaters

The first, and most obvious benefit of an aquarium heater is that it’ll heat your betta’s tank water to a temperature that’s healthy for it. It isn’t easy to manually heat an entire aquarium of water to an appropriate, constant temperature warm enough for a betta fish, which is why we recommend a heater.

Aquarium heaters monitor and control the water temperature in a betta tank so you don’t have to. They also stabilize the water temperature and eliminate drastic temperature fluctuations.

Do Betta Fish Need a Heater?

Yes, betta fish need a heater in their tanks unless the temperature of the outside environment is consistently above 78 degrees Fahrenheit. As previously mentioned, betta fish will become sick and risk death if they’re kept in colder temperatures. Aquarium heaters are the most reliable way to maintain a stable temperature in your betta fish’s tank.

What Type of Heater Does a Betta Need?

Submersible Heaters

Submersible heaters are the most common types of aquarium heaters (and for good reason). As the name suggests, these heaters are completely submerged into the water, efficiently distributing heat. 

You can place the heater horizontally or vertically at the top of the water, or deep into it. Don’t place it onto the substrate, however, because it has a different heat conductivity than the water and could damage the heater or glass tank. 

Our favorite submersible heater is the INKBIRD Titanium submersible heater. This heater has two wattage settings: 100W for 5 to 20 gallon tanks and 300W for 50 to 60 gallon tanks. It’s made of titanium, which is much more durable than other common submersible heaters and has a remote control to adjust the temperature settings. It also has overheat protection and water shortage protection, so it’ll stop heating if the water is too warm or if the heater is not fully submerged underwater. 

Immersible/Hang-on Heaters

Immersible heaters are hung over the side or back of a fish tank. Some parts of the heater are immersed into the water and some parts are kept outside the water. These are typically made of glass with the heating element on the inside and a water line marking the highest possible water level on the heater.

Immersible heaters don’t provide as effective heating as submersible heaters because they lose heat in the part of the heater that’s above water. The immersible heater is often found in small aquarium kits, but we would recommend choosing a submersible heater if you have the option as they’re completely underwater and more effective.

In-Line Heaters

In-line heaters are installed on the outside of the tank and function alongside a water pump or filter to move the water through them. These are less common, but are well-liked because the water’s temperature is kept very steady. They are also well-liked because there are no unattractive objects inside the aquarium. 

This ISTA in-line heater is our favorite in-line heater. It’s available in 3 wattages: 150, 300, and 500, it’s easy to install, and the temperatures are accurate. It reads in Celsius, so for your betta fish, set the temperature between 24 and 27 degrees.  

Substrate Heaters

Substrate heaters are cables or coils laid beneath the substrate in your aquarium. They’re designed to heat the gravel or sand at the bottom of the tank, which will then radiate heat up into the water. They are another hidden heater, maintaining a visually appealing look inside the aquarium. 

This type of heater is particularly beneficial to keeping a warmer temperature in the tank for aquarium plants to thrive. With other heater types, the substrate can act as an insulator, keeping the roots of plants at colder temperatures. Alternatively, substrate heaters heat the substrate and the water. 

Filter with Heater

Some aquarium filters come with built-in heaters. Similar to the in-line heater, water is heated and filtered simultaneously, but the filter and heater are built combined, instead of separately.

The Biostyle Thermo Aquarium Filter is the best power filter/heater we have tried. There is a 30 gallon version and 50 gallon version and they’re sleek and attractive. It’s effective in both filtering and heating, keeping aquarium water at a steady 79 degrees Fahrenheit, perfect for your betta.

How Can I Keep My Betta Fish Warm Without a Heater?

Though we don’t recommend taking care of a betta fish without using a heater, there are sometimes reasons why you may need to manually warm your betta’s tank water. Maybe you’re in the process of finding a heater, your old heater broke, there was a power outage, or you just didn’t know you needed one. If you find yourself in a situation where you need to manually warm your betta’s tank temperature, here are a few suggestions:

1. Use a Smaller Tank

Though small tanks are not ideal for betta fish (we recommend at least 5 gallons), in situations where you need to have more control over the water temperatures, a smaller tank size could be beneficial. Heat control is much easier with a small tank of water than a large tank. 

2. Increase the Room Temperature

One way to keep your betta’s water warm without a heater is by heating the room that houses the aquarium. We recommend heating your room to at least 78 degrees to try to sustain warm temperatures in the betta aquarium. 

3. Insulate the Walls of the Betta Fish Tank

There are lots of DIY ways to insulate your betta tank. Start with putting a lid cover over the tank. You can use what you have in your house, but use tin foil and styrofoam if you have it and wrap it around the entire tank. The insulation should retain the warmth inside the tank for a longer period of time.

4. Direct Sunlight

As I’m sure we are all aware, the sun is a reliable source of heat. Putting the tank in direct sunlight is a good wait to add a little warmth to the aquarium water.

5. Strong Aquarium Lighting

Alongside sunlight, artificial light is a heat source as well. With some strong aquarium lighting, you should be able to add some heat into the fish tank.

6. Hot Water Bottles

Another way to heat betta tanks without a heater is with hot water bottles. You can put almost boiling water into plastic bottles or packages and float a couple on the surface. The heat will transfer from the bottles into the water and keep your bettas warm. 

Important tip: increase the water temperature range slowly

When you’re finally able to introduce (or re-introduce)a heater into your betta’s tank, it’s important to slowly increase the water temperature. If the temperature of the water increases too fast, it can lead to temperature shock. Drastic changes in a betta’s tank cause stress, even if it’s the correct temperature for a betta habitat.

Heat Is the Key to Tropical Fishkeeping

Betta fish thrive in warm water, so as a betta owner, it’s important to keep your fish tank at a warm temperature. Betta fish need water at around 76 and 80 degrees Fahrenheit, and without a heating system, your betta’s health may be at risk. Aquarium heaters are easily found at fish and pet stores (or shop our recommendations throughout this article) and are an essential part of giving your betta a healthy, long life.