After the traditional goldfish, betta fish are the most popular pet freshwater fish on the planet. However, unfortunately, one myth surrounding bettas is that they can be kept in unheated vases or bowls.
So, what’s the issue with that? And what’s the optimal temperature for betta fish?
Keep reading to find out the ideal temperature for your beloved pet betta fish.
What Is The Ideal Water Temperature For Betta Fish?
Bettas are tropical fish that must have warm water to thrive.
The ideal water temperature for betta fish is between 75° and 80°F. A stable betta tank temperature is vital for your pet, as fluctuations in water temperature stress your fish, causing health problems.
Why Is That Temperature Important For Bettas?
As previously mentioned, bettas are tropical fish. Betta fish, or Siamese Fighting fish are native to the tropical regions of Thailand. In their natural habitat, bettas live in shallow ponds, rice paddies, and marshes with constant warm temperatures. Pet bettas also need to live in a stable environment to remain healthy, and that includes the correct water temperature.
Although your betta fish can survive outside of water temperatures of his ideal range of 75° and 80°F, he won’t thrive. Bettas can suffer if the water is too cold but equally if their water is too warm.
So, whereas bettas will survive in temperatures as low as 72°F and as high as 86°F, your pet won’t thrive. The 78° and 80°F temperature range is described as the “thriving range” by many betta breeders and enthusiasts.
Basically, if your betta’s fish tank temperature falls below 72°F or rises above 86°F for more than an hour or so, your pet could suffer temperature shock, and there’s a chance that you could even lose your prized betta fish.
What Is Temperature Shock?
All fish species can suffer from temperature shock, including bettas, and that can be deadly.
Temperature shock is the body’s reaction to large or rapid temperature changes in temperature, resulting in hyperthermia and hypothermia. In fish, temperature shock happens because the fish is unable to react or adapt to changing conditions. In such circumstances, the fish’s body cannot function properly and begins to shut down.
In tropical species, such as bettas, it’s usually cold temperature that cause major problems.
What Causes Temperature Shock?
There are a few ways in which temperature shock can happen.
Failure To Acclimate New Fish
When you buy a new betta, the chances are that the water temperature in his fish store tank will be different from that in his home aquarium. For that reason, you need to acclimate your fish carefully before releasing him into his home tank.
I recommend that you float your betta in his bag in the new tank for at least an hour so that the temperatures equalize. That way, the water temperature gradually adjusts so that your fish won’t get shocked. Once the temperatures have matched, you can introduce your new betta to his home.
When carrying out weekly partial water changes as part of your tank maintenance regime, be sure to check that the temperature of the new water is the same as that in the tank. Adding a bucketful of cold water to the tank is sure to make the temperature plummet, potentially endangering your betta buddy.
So, make sure that the water you’re adding to the tank is the same temperature as that in the tank by using an aquarium thermometer to check before you top up the tank.
You should always use a heater for tropical aquarium fish tanks rather than relying on room temperature. Wild swings in room temperature can drastically affect the water temperature in your fish tank, especially in smaller setups. So, use a heater or even a chiller if you live in a very warm tropical climate.
Temperature shock can be caused by heater failure, which is a common problem. Unfortunately, cheap heaters frequently fail overnight, either overheating your aquarium completely or failing to switch on, leaving your poor fish shivering in cold water.
So, always buy the best quality heater you can afford to minimize the risk of failure.
Also, you need a reliable aquarium thermometer so that you can check the water temperature every day and take action if you need to. If you discover a problem with the water temperature, warm or cool the water gradually, or you risk shocking your betta even more.
The Labyrinth Organ
Bettas are labyrinth fish, using their specially developed labyrinth organ to periodically breathe atmospheric air at the water surface. Bettas need to top up the dissolved oxygen that they derive from the water by breathing air through the labyrinth organ. Otherwise, the fish’s body can’t get the oxygen it needs to function.
The labyrinth organ is extremely sensitive to temperature changes. For your betta’s labyrinth organ to function properly, the ambient air temperature must be close to or the same as the water temperature. So, if the water temperature is unstable, there’s a good chance that the labyrinth organ will be damaged, and the betta won’t get enough oxygen.
How Can You Tell If Your Betta Is Too Warm Or Too Cold?
Your betta’s behavior will give you a good indication if there are problems with the water temperature.
Water Too Cool
Bettas cannot survive in cold temperatures for a prolonged period. If the water in your betta’s tank is too cool, your fish will most likely become noticeably more lethargic than usual. That’s because cold water temperatures slow down the betta’s metabolism or bodily functions, causing a loss of appetite and general lethargy.
So, your fish might stop eating and swimming, and his respiration rate could slow down, too. It’s not uncommon to see a betta resting on the substrate or on tank decorations and plants much more than he would typically do. That’s because your pet simply doesn’t have the energy to move. Consequently, complications can arise, such as bacterial diseases, including fin rot.
Also, because the betta’s metabolic function is too slow, his immune system will be compromised, and he will be stressed. That leaves your pet vulnerable to bacterial infections and attack by parasites.
Water Too Warm
If your betta’s aquarium water is too warm, you’ll see that your fish is much more active than usual to the point of becoming hyperactive.
Your fish will dart around his tank in a frenzy without pausing to rest, sometimes even burrowing into the substrate.
Because the excess heat makes the fish’s metabolic rate run faster, he will need more oxygen. So, you will notice that your pet’s respiration rate increases, and he will make more frequent trips to the surface to breathe through his labyrinth organ. The betta might even hang at the top of the water column where the temperature is slightly cooler and there’s more oxygen available.
Ultimately, the betta’s cardiovascular system becomes overloaded, and the fish suffocates because he can’t get enough oxygen to support his body’s requirements.
It’s worth noting that tank size can play a part in overheating. Generally, a smaller 5-gallon tank will overheat more quickly than a larger tanks.
Other Symptoms Of Temperature Shock
Other signs to look out for include a loss of color or gradual fading that can take weeks or even months to recover once the temperature has been corrected.
If My Fish Tank’s Water Is Not At The Right Temperature, What Can I Do?
The most important thing to remember when adjusting the water temperature in your betta’s tank is to do it gradually. If you suddenly heat or cool the water, you risk shocking your pet even more!
So, warm or heat the tank by only a couple of degrees over a few hours.
Warming The Tank
To warm the water, set an aquarium heater to the appropriate temperature, and monitor your thermometer carefully to ensure that the water heats up gradually.
You can also make small water changes every few hours with warmer water to slowly raise the temperature. If there’s a power outage, try wrapping blankets and towels around the outside of the tank to retain as much heat as possible. If you have one, use an air pump to increase the level of dissolved oxygen in the water.
Don’t add hot water to your betta’s tank, as that could shock him even more!
Cooling The Tank
- First of all, set your aquarium heater to the correct temperature and make sure it’s working properly. Don’t turn the heater off completely, as that could cool the water too quickly.
- Now turn off the lighting unit and open the tank lid to allow heat to escape and prevent further heating.
- If possible, have a fan blowing across the water surface to increase evaporation rates and remove heat.
- Float small bags of ice in the tank to slowly reduce the temperature.
- Use small water changes with cool water to reduce the temperature.
- Use an air pump to keep oxygen circulating around the tank.
I hope you enjoyed our guide to the ideal aquarium temperature range of water for betta fish. Please share if you did.
Bettas need a stable water temperature of between 75° and 80°F that replicates their natural environment. If the temperature in the tank environment falls too low or climbs too high, that could spell disaster for your pet. Use a reliable heater that you can program with the correct temperature for your fish, and fit an accurate digital aquarium thermometer so that you can keep an eye on the water temperature in your betta’s tank.