Betta Fish Water Temperature Guidance Range

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perfect water temp for betta fish

Also known as fighting fish, betta fish are some of the most popular aquarium fish. If you want your betta fish to survive and be healthy in your aquarium, you must ensure that the water is at the right temperature.

Like other creatures, betta fish are sensitive to too cold or cold water temperatures. So, what’s the perfect water temperature for a betta fish?

For your betta fish to survive and thrive in your aquarium, the ideal water temperature is between 78 and 80 degrees F (25-26.5 degrees C).

RangeTemp (Fahrenheit)Temp (Celcius)Behavior
Optimal78 – 80 Degrees(F)25.5 – 26.7 (C)Normal & Healthy
Too Cold, But Survivable72 – 77 Degrees (F)22.2 – 25 (C)Slow & Lethargic
Too Cold, FatalUnder 72 Degrees (F)Under 22.2 (C)Coma & Death
Too Hot, But Survivable81 – 86 Degrees(F)27.2 – 30 (C)Frantic & Fast
Too Hot, FatalOver 86 Degrees (F)Over 30 (C)Hyperactive & Death
Survivable and Optimal Tank Temperature Ranges For Betta Fish

If the water is colder than that, the fish’s immune system will slow down, and if it is hotter, the fish will be stressed and age faster.

To ensure that these temperatures are always optimal, you need to have a thermometer close to you. Experts recommend that you check the temperature at least once daily.

Why Is 78-80 Degrees Farenheit The Best Temperature?

The natural habitat for betta fish is in tropical areas. They come from temperate climates of Myanmar (Burma) and Thailand, where these are the normal water temperatures. Some people have suggested that domesticated betta fish do not need to remain under those water temperatures, but it’s not correct.

While they can survive outside the 70-80 degree (F) temperature range, they will not be comfortable and it’s not healthy for them. They will also not thrive or multiply how you want them to. Living below or above that range, the fish will survive but not be completely healthy and not thrive.

Living at the correct water temperature ensures that your fish has the correct amount of oxygen. It also helps maintain a perfect metabolism to keep your fish active but not too active, plus it increases their lifespan.

Mostly, water temperatures change during water changes, when you add something to the tank, and when there is a change in your room temperature. Therefore, you have to monitor the water temperature closely if any of these happen.

If you find it hard to maintain the water temperature on the required range, it’s better if the water gets warmer than colder.

Survive Vs. Thrive Temperatures For A Betta

Minimum / Maximum Survival Temperatures

Surviving means that your fish is uncomfortable but can still withstand the water temperatures. On the other hand, thriving means that the fish are most comfortable, their immune system is the strongest, and they can reproduce perfectly.

The perfect thriving temperature range is between 78 and 80 degrees F. However, they can survive a temperature range between 72 and 86 degrees F.

If the temperatures go below 72 degrees F or above 86 degrees F and remain that way for over an hour, your fish will have low chances of survival.

The closer you are to either 78 or 80 degrees F, the better, happier, and healthier your fish will be.

Is 72 Degrees Okay For A Betta Fish?

A betta fish can survive for a short time in the water with a temperature of 72 degrees. However, it is not recommended that you let it live there for too long. That is because very cold temperatures (for a betta) will lower the immune system of your fish, which could cause it to die faster.

Therefore, you need to ensure that you increase the water temperature.

The best long term solution for warming up your betta tank is a fish tank heater. They can be set to the optimal temperature and will automatically regulate it for you. When your tank is too cool, it will turn on and bring the temperature up. When your tank is warm enough, it will turn off and keep the tank at the optimal temp.

If you need a quick, short term solution these are a few temporary ideas.

  • Adding a hot water bag to the water
  • Wrapping the tank in a warm towel or anything to warm up the water
  • To maintain the warmth in the water tank, try closing the lid but do not leave it closed for too long to allow for air exchange.

What Is The Minimum Temperature That Kills A Betta Fish?

Anything below 72 degrees F is too cold for your fish, and it will likely not survive very long. If the water is at 70 degrees F, it is too low for your fish, and it will probably not survive if you do not take immediate action.

Since the water temperature at the bottom is usually cooler than that at the top, you will notice that your fish has suddenly moved to the top of the tank.

If you notice that, it is time for you to start thinking of ways to increase the temperatures of the water in the tank-like moving the tank away from windows into the warmer parts of the house.

What Is The Maximum Temperature That Will Kill Your Fish?

Your fish can survive temperatures of up to 86 degrees F. Anything above that will kill it quickly. If the temperatures are too high, you might notice your fish exhibiting unusually rapid swimming patterns.

While hot water temperatures may not kill your fish as fast as cold water temperatures, they will reduce its lifespan.

Suppose you notice water temperatures are above 86 degrees F. In that case, you need to do something to cool it, like moving it away from heat emitting devices, adding a cold water bag into the tank, bringing a fan close to the tank, turn off the heater, change the water, or turn off the lights.

Is 84 Degrees F Too Hot?

84 degrees is outside the perfect temperature range for your betta fish, but it is not necessarily deadly. Your fish could survive, but it will be uncomfortable and exhibit signs of stress. 84 degrees F also reduces the lifespan of your fish.

High temperatures increase the metabolism of your fish, which results in making it age faster, hence faster death. Your fish will also come to the tank’s surface because the warmer water at the surface of the tank does not have enough oxygen for the fish.

What Happens Outside The Thriving Temperature Rage?

Knowing the symptoms that your betta fish will exhibit when the water is too hot or cold is important to help save its life.

Betta Fish Symptoms When The Water Is Too Cold

When the temperature of the water tank drops below 78 degrees F, some of the symptoms that your fish will exhibit include:


This is one of the most common signs of a fish experiencing a cold temperature shock. Fish are cold-blooded, meaning they only absorb heat from the water. When the water is too cold to generate any heat for the fish, the fish stops moving.

This is because the cold temperatures slow down the fish’s metabolism, making it hard for them to swim or make any movements. With that inactivity also comes a loss of appetite.

Resting on the floor of the tank

Since your betta fish has lower metabolism, they lack the energy to swim to the top of the tank. Also, the water at the bottom may be warmer than the one at the top.

Becoming sick too often

Coldwater reduces the immunity of your betta fish, making it more vulnerable to fungal, bacterial, and parasitic infections, plus other diseases.

Slipping into a comma

This happens only at very low temperatures, and if it does, you have to act immediately if you want to save your fish. This happens when the metabolism levels are too low, and your fish gets low oxygen to the brain.

Betta Fish Symptoms When The Water Is Too Hot

Breathing rapidly

When the water is too hot, it does not have as much oxygen as cooler water, making the fish breathe rapidly. You will also notice that your fish will remain at the surface more than it normally does. That is because there is usually a pocked of oxygenated water just below the water surface.

Erratic swimming

Hot water increases the metabolic rates of your betta fish, which gives it too much energy. That makes it swim faster and more erratically from one side of the tank to the other. You might also notice other weird swimming behaviors like burrowing into the gravel.

The high metabolic rates will also cause your fish to age faster, which reduces its lifespan.

Is Room Temperature Okay For My Betta Fish?

I’m not sure where the image in my head came from (perhaps commercials) that show a simple bowl on a counter with a betta fish in it looking quite happy. Unfortunately, room temperature water is usually around 68-72 degrees F, which means it is too low for your betta fish, and it will kill the fish within minutes. Therefore, you should always have something to increase the water temperature to the perfect thriving range.

You can do that using a heater, lights, hot water bag, or wrapping the tank in a hot towel. You should do most of these things during the cold seasons when the temperature around the house is low.

Is The Water Temperature The Same As My Room Temperature?

No. Room temperature is the ambient temperature of a normal room, usually between 68 and 72 degrees F. the water in your fish tank will always be lower than the room temperature of the room you place it in.

However, the temperature difference is not usually that great and is mostly around 1-2 degrees F. It depends on the initial temperature of the room, the time the tank has been in the house, and the volume of water in the tank.

What Happens If The Water Temperature Changes Rapidly?

While it is essential to try and cool or warm the temperature of the water in your fish tank, you have to ensure to do it slowly. Betta fish are sensitive to rapid water changes, which could have effects like bloating, shock, and other illnesses. This is another reason why it is important to properly acclimate your betta to a new fish tank or environment.

If you change the water in the tank, ensure that the new water is the same temperature as the previous one or gradually change it.

Do I Need A Water Heater For My Betta Fish?

If you live in a place that has consistent temperatures of below 75 degrees F or an area that experiences extremely low temperatures at certain times of the year, having a water heater is a great idea. There are many brands and models available in the market, depending on the size of your fish tank.

Ensure that you choose the best quality water heater for long life and get the best temperatures.


If you want your betta fish to have a long, happy, and healthy life, you always have to check the temperature of the water it lives in. for that, ensure you have a high-quality thermometer close to you always.

You should also know your fish’s symptoms if the water is too hot or cold and know different ways of adjusting the temperature.

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