Do Betta Fish Need A Heater In The Summer?

Betta fish are a popular pet fish that is a tropical variant. This means they need consistently high water temperatures, which results in most betta fish owners buying a heater for their pets. But what about in the summer, when the temperatures are higher? Do betta fish still need heaters?

In the summer, you should turn down your heater but not turn it off. A sudden change in temperature will cause more harm than good. Parasites can come into the tank and reside there thanks to the temperature drop, and your betta fish can panic and become stressed due to it.

The rest of this article will cover if your betta fish needs a heater, if they need one in the summer, why an aquarium heater is essential in the summer, how to keep your fish warm without a heater, recommended heaters, and FAQ.

Why Your Betta Fish Needs A Heater

As mentioned previously, betta fish are tropical fish. This means they need heaters to stay alive. They live in high temperatures in the mid-70s to mid-80s. Your aquarium needs to meet these demands; otherwise, the betta fish will die. You cannot keep them in low temperatures.

Heaters are the most effective way to keep your betta fish at a comfortable temperature. Although it’s important to mention that if your room is consistently in the required temperature range, you don’t need to have a heater. However, it’s highly recommended.

There are other benefits to having a heater. Having temperature control is good for the fish, and even if you have a consistently high-temperature room, a heater is still the best way to ensure the environment won’t ever drastically change.

With a controlled environment, a heater can actually improve a betta fish’s immune system. It also keeps them comfortable and happy when they’re at a consistent body heat. Without a heater, your room temp will vary depending on the season, and that can stress a betta fish out.

Betta fish

Why Your Betta Fish Needs A Heater In Summer

Your room temperature will go up during the summer, but that doesn’t mean you should turn your heater completely off. For starters, there’s a chance you could forget to turn it back on during a cooler day in summer. If this happens, your betta fish could die.

Therefore, the best solution is to turn it down, but not off. This way, you’re still in control of the environment in case something goes wrong, but you can also let the natural state of the room dictate the temperature of the aquarium. 

If you turn the heater off and the temperature changes drastically, this will cause extreme discomfort for your fish even if the temp is in their liveable range. It will stress them out and cause health issues if it goes untreated for too long.

Why An Aquarium Heater Essential In Summer

It’s good to keep your betta fish in a room with a naturally high temp. However, having a heater is essential in summer despite the warm weather. As mentioned above, heaters have more benefits than just keeping your fish warm. There are also health benefits that come with it.

One of the worst things you can do to your betta fish is make them unhappy. When they’re in bad health, they’re stressed and unhappy. A heater prevents unhappiness and stress, which is why it’s an essential tool even when in the blistering heat of the summer.

It also gives you peace of mind knowing you don’t have to worry about sudden weather changes or anything of the sort. It’s a small price to pay for permanent relief and keeping your betta fish happy. If your betta fish isn’t happy, then it can develop health issues.

A health issue that can develop is fin rot, which is exactly what it sounds like. Your fish will also lose its color and become less vibrant. Keeping them happy isn’t just for their personal enjoyment; it’s also for their health, so make sure to keep them happy and not stressed.

How To Keep A Betta Fish Warm Without A Heater

If your heater breaks, or if you choose not to buy one, you’re going to have to keep your betta warm. Luckily, there are a few ways you can do this. The first is getting a lid for the tank to keep the heat inside. Trapping the heat inside the water keeps it at a consistent temp.

You should have a thermometer on the ready to check the aquarium’s heat, and you can make adjustments from there. It’s smart to have a thermometer or thermostat in the room you’re keeping them in no matter if you have a heater or not.

Another solution is to throw blankets and towels in the dryer and let them get hot. Not warm-hot. When they’re hot, wrap them around the tank and put more towels and blankets in. This will prepare you for when the current layers you’re using get cold.

If you have a smaller fishbowl, you can use a heating mat or pad. These will stay warm consistently, and they’re a cheap solution if you’re waiting to get a new heater. You can get them at your local Walmart or Target, or you can order them online.

Lastly, you can use stronger lights. That may sound silly, but stronger lights actually do help warm the tank. If you combine a lid, layering blankets, and stronger lights, your tank will be at a liveable temperature. Keep checking your thermometer, just in case.

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Recommended Heaters

Choosing a heater can be tough, but the first step is to judge your tank size compared to the watts you’ll need to heat the water. The bigger the tank, the more watts you’ll need. Keep that in mind while shopping for heaters. The best place to get a good heater is at your local pet store.

The reason why it’s best to get it in person is so you can transport it yourself, see it with your own eyes, and consult the workers about which ones work best. Although ordering online does work, you reduce the risk of breakage if you take it home yourself.

For starters, your heater should provide 3 to 5 watts for every gallon of water. Using this math, if you have a 10-gallon tank, you’ll need a heater that provides between 30 and 50 watts. Or, you can use two 20-watt heaters.

The Fluval E Electronic Heater can supply either 100, 200, or 300 watts, depending on which size you get. It can go up to 93 degrees and has an auto shut-off feature. It heats up to 100 gallons of water. It’s easy to use and understand, making it a perfect choice for your fish.

If you’re looking for something that comes in smaller sizes, the EHEIM Jager Aquarium Thermostat Heater is for you. It goes as low as 25 watts and as high as 300, also heating up to 100 gallons of water. This heater goes to lower temps than the Fluval, and it’s a wider heater.

Lastly, there’s the Fluval M Submersible Heater. It’s cheaper when compared to the other two options, but it still covers a lot of gallons. It’s in the 50-200 watts range and can cover 15-65 gallons. It has a mounting bracket that makes it easy to install, and it has a simple design.


With all the care that goes into owning a fish, there are lots of questions to answer, such as: can betta fish live without a heater? What temperature is too hot for betta fish? and what temperature is too cold for betta fish?.

Can Betta Fish Live Without A Heater

Betta fish can live without a heater. If the room temperature is high enough all year round, then that makes it a suitable environment for the betta fish. But this is only if the room is hot enough all year, during each season, even in winter. Check this by using a thermometer or thermostat.

The room needs to be consistently over the required temperature. It can’t be at the very lowest a betta can survive since if it dips under while you’re not around, then you’re risking their lives. You should either keep them in a room that can withstand the required temp or get a heater.

What Temperature Is Too Hot For Betta Fish?

A betta fish has a temperature range of mid-70s to mid-80s. As tropical fish, they do enjoy high temps. However, there is a limit. If you set your heater too high, your betta fish will slowly roast and die in the water. This is why you should monitor the temperature to ensure it doesn’t overheat.

The temperature that’s too high for betta fish is anything over 86 degrees Fahrenheit. If the water temp remains higher than 86 degrees for more than an hour, your betta fish will die. However, heaters are reliable, so you won’t have to worry about this too much.

What Temperature Is Too Cold For Betta Fish

Contrary to the high temps, the low temps are deadly to betta fish too. Similar to the highs, the low temps being on for more than an hour will kill your betta fish. This is why having heat supplied to them in winter is crucial. Otherwise, if you don’t kill the fish, you’ll make them stressed.

Below 74 degrees Fahrenheit is the cut-off point. They can survive a little while in that temperature, but the shock will start to kick in quickly. Another thing to consider is that 72 and below will kill your betta very fast. They can survive over an hour at 74 degrees but not below 72.

If you’re worried about the temperature going too low, then you should consider getting a lid for your tank to keep the heat contained. Also, have a thermometer on the ready to check your aquarium at any time. Keep the temp consistent, and you’ll have a happy and safe betta.

Keeping a consistent environment leads to happier and less stressed betta fish, meaning they’ll be more eager for feedings, they’ll interact with their toys and tankmates, and they’ll swim fluidly. You can read more about temperatures and how they affect betta fish here.


To recap what we covered, betta fish don’t need heaters to survive, but they should have a consistently high temperature in all seasons. In summer, you should turn down your betta’s heater, but not turn it off. Turning it off may result in sudden temperature drops.

If you don’t have a heater or your heater broke, there are other ways to keep your betta fish warm. The best solution is to put a lid on the tank to contain what heat is present inside the water. You can also combine this with stronger lighting to heat up the fish.

Another solution is to put towels and blankets in the dryer and get them hot. Not warm-hot. When they’re hot, wrap them around the tank and let the warmth heat up the water. Put more towels and blankets in the dryer and switch them out when the old fabrics get cold.

If you’re buying a heater, it’s recommended that you buy from your local pet store. Buying it in-person means you can transport it safely and ask questions about the product you’re buying.