Important Guide to Betta Fish Water Temperatures

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Betta fish are freshwater fish whose natural habitat consists of tropical regions. They are also called Siamese Fighting Fish because of their fascinating history of being bred as a fighting fish. In their native habitats Bettas live among the marshes and shallow ponds of Asia, especially the regions around Southeast Asia.

Bettas have the ability to adapt to environmental changes quickly, even though they can be somewhat high maintenance. The most important thing to remember when taking care of Bettas is to maintain the proper water temperature. 

The water temperature significantly affects a Betta’s homeostasis. If there are any fluctuations or variations from the appropriate water temperature, your fish’s metabolism will get off balance, which can cause a variety of health problems and even infections.

Most Bettas are curious and friendly when it comes to their owners. When not cared for properly, you Betta can become aggressive towards other fish, as well as depressed. Their aggressiveness has been exploited among the pet traders, compromising their habitat.

Because Bettas live in tropical climates, they can survive in mild water temperatures. However, Bettas do have an armor system for defense against sudden climate changes. Moderate increases in your tank’s water’s temperature will not affect your Betta. However, extremely low temperatures and high temperatures can cause severe issues with your Betta’s overall health.

This guide will walk you through everything you need to know about maintaining the correct temperature for your Bettas. All it takes is a little effort to ensure your Bettas have the proper tank maintenance, meeting their needs for the healthiest environment you can give them.

Because Bettas are naturally tropical fish, their ideal water’s temperature ranges between 76°F – 82°F. If you plan to house your Betta in a smaller tank, we recommend nothing smaller than five gallons.

Making sure that the water temperature remains between 76° – 82°F will ensure your Betta’s optimum health. Experts agree that your Betta’s water temperature should not go below 74°F or exceed the recommended 82°F. If the water’s temperature drops too low or goes too high, your Betta could get hurt or sick and possibly even die.

The Reasons Bettas Need These Temperatures

For Betta’s, balancing their body’s internal temperature, or homeostasis, can be sensitive. Differences in the water’s temperature can affect your Betta’s homeostasis severely, which could, in turn, compromise their immune systems.

If you witness fatigue and weakness in your Betta, as well as abnormal behavior, a dangerous fluctuation of the water’s temperature may have occurred. Considering that the natural habitat for your Betta is a tropical one, maintaining the water’s temperature is essential for your fish to live a long, healthy life. 

Unfortunately, mimicking your Betta’s natural environment with all the organic nourishment that is available in the marshes and rice paddies is impossible. However, you do have command over the water temperature, which you can mimic from their natural habitat. 

In their natural habitat, the water’s temperature remains steady all year long. Therefore, your Bettas can not handle wide fluctuations is their water’s temperature. Because Bettas can’t adjust their own internal body’s temperature, they are greatly affected any fluctuations in the water’s temperature around them. 

When a fluctuation in the water’s temperature occurs, these changes will negatively affect your Betta’s feeding, respiration, and their ability to swim. By consistently maintaining the proper water temperature, your Betta’s metabolism system will remain healthy, thereby extending your Betta’s life span. 

When the Water Temperature Gets Too High

Because it does not contain as many oxygen molecules as cold water does, hot water can cause severe damage to your Betta’s metabolism system. In an effort to get more oxygen into their bodies, your Betta will begin to breathe rapidly and even stay at the surface of the water, gulping oxygen. 

You might also see them swimming erratically, which will cause your Betta’s metabolism rate to increase. The higher metabolism rate can quickly deplete them of energy, causing extreme fatigue in your Betta. 

This level of fatigue can have adverse effects on your Betta’s overall health. If continued, the high metabolic rate will cause premature aging, causing their lifespans to shorten significantly. 

When the Water Temperature Gets Too Low

Colder temperatures will have the opposite effect on your Betta than hot water. Instead of speeding up your fish’s metabolism, the cold water will slow their metabolism rate down significantly. 

When temperatures drop below 74°F, your Bettas will not be able to maintain a healthy body temperature, which will make it extremely difficult for them to function and survive in the colder water temperatures.

The cold water will make your Bettas lethargic. You will see them in the bottom water level of your tank, swimming slowly or not at all. Because the water temperatures tend to be warmer towards the bottom of the tank, your Bettas will seek out that warmth rather than trying to get more oxygen. Your Bettas are also in danger of starvation because they will stop eating when the water is too cold.

When the water temperature drops drastically, your Betta is in danger of slipping into a coma. While in the coma, their metabolism will slow down to the point where they become defenseless against infections, diseases, and bacteria, all of which can damage their immune system to the point where your Betta could die. 

The Importance of Maintaining the Proper Water Temperature

The water temperature from their native habitat remains at a steady temperature, which Bettas are most accustomed to. However, your aquarium’s water temperature can fluctuate with the changing weather conditions and the room temperature.

Any water temperature outside of the healthy range of 76 to 82°F will have your Betta struggling for survival in those extremities. The water temperature fluctuations will concentrate whatever damage that occurs to the metabolic and immune systems. These fluctuations in the water temperature can have several different results.

Temperature Shocks

Extreme hot and cold water temperatures can cause your Betta to suffer temperature shock, which leads to lethargic behavior, coma, and even death, eventually. 

Changes in Their Metabolic System

Your Betta’s body temperature will fluctuate along with the water temperature. Homeostasis kicks in when the Betta’s body becomes too cold, causing a decrease in the metabolic activity, which helps it preserve the body’s warmth. The decrease in their metabolism will cause appetite loss, fatigue, lethargy, and finally, a coma. 

However, your Betta’s metabolic activity will increase, causing your Betta to display hyperactivity when the water temperature becomes too warm. Your Betta’s overall health will be in danger of becoming stressed, leading to an burnout of energy. Your fish will become extremely distressed as it endures increased changes in their metabolic activity. 

Respiration Issues

The oxygen levels will change along with the water temperatures, as well. When water temperature decreases or increases, the oxygen levels will fluctuate, causing adverse reactions in your Betta. 

As mentioned previously, oxygen levels will drop dramatically when the water temperature gets too hot. You will see your Betta hovering at the surface of the water, gulping air in order to get enough oxygen in their system. The low oxygen levels will hinder their respiration, which will eventually damage their metabolism’s rate. 

Immune system

The stress and distress that your Betta goes through when there are fluctuations in the water’s temperature will eventually damage your Betta’s immune system. The water’s temperature can cause bacteria to breed in the water when the fluctuations become extreme. If a Bacteria infestation occurs, your Bettas will be in danger of infections and diseases. 

An infestation of bacteria, along with a weakened immune system, will cause your Betta to get sick faster and more often. As your Betta’s immune system weakens, your Betta will be vulnerable to a variety of diseases and conditions. 


When fluctuations in the water’s temperature cause the immune system to weaken, it won’t be able to fight off possible diseases and infections effectively. For example, your Betta can contract fin rot, which is quite common in Bettas. Fin rot is where bacteria will attach itself to, and feed on, the Betta’s fins, eventually spreading across the entire body. 

Parasites can also breed in extreme water conditions, attacking your Bettas and inducing infections that can range from mild to critical. Water fluctuations can also cause internal issues, such as appetite loss and constipation. When the water temperatures drop and become too cold for your Betta, it will stop eating and eventually starve. 

Maintaining a Constant Temperature

As you can see, maintaining the water’s temperature is essential for your Betta to survive and remain healthy. Incorporating the following suggestions in your routine will go far in ensuring the water temperature in your Betta’s tank remains at an ideal level.


Using a thermometer will help you to monitor the water’s temperature in your Betta’s tank. Buying a separate thermometer will give you more accurate results than the tank’s thermostat. Floating thermometers with suction cups will work well for maintaining the water’s temperature most accurately. 


A heater is essential in maintaining the water temperature of your Betta’s tank. When you buy a quality heater, you can rest assured that it won’t break down and work more efficiently. Poor quality heaters have a tendency to overheat the water, which is dangerous for your Betta. Using a heater in conjunction with a floating thermometer will ensure your Betta’s tank will stay at a consistent, healthy temperature.

You might also be interested in: Betta Fish Heater – Your Betta Will Love [2020]

Water Changes

When performing partial water changes in the tank, you must make sure the water’s temperature does not change. Drastic changes in the water’s temperature will cause your fish to go into shock. If the water temperature does get too cold or hot during a water change, you can help bring the water temperature back to normal by adding water or installing a heater. 

Setup Your Tank in the Ideal Spot

If you live in a region with extreme hot or cold temperatures, you will want to keep your aquarium tank far from the doors and windows of your home. In colder regions, heaters and lamps placed close to the aquarium will help maintain the water temperature. 

For climates that are warmer, avoid setting up the tank near direct sunlight. Use air conditioners and fans to keep the water’s temperature from fluctuating too much in the heat. 

Aerating the Water

Fluctuations in the water temperature can cause a decrease in your tank’s available oxygen levels. One thing you can do to ensure that the oxygen levels in the tank’s water remains steady, is to purchase an aerator. This will ensure there is enough oxygen in the water for your Bettas to breathe comfortably.


Your Betta’s health will be adversely affected when there are changes in the tank’s water temperature. Mild deviations can be tolerated, as long as they are minimum. However, drastic changes can risk your Betta’s health by weakening their immune systems and reducing their oxygen levels. 

By following the advice outlined in this guide, you will be proactive in ensuring your Bettas live a healthy, happy, long life. 

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Michele Taylor
Michele Taylor

Hello, fellow aquarists! My name is Michele Taylor, and I am a homeschool mother of six children, which includes five boys and one girl. My kids range in age from five-years-old to eighteen-years-old.

Growing up, our family had a large aquarium with angelfish, goldfish, and lots of different varieties of neons. We also had a “suckerfish” that grew to be about six inches long.

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