We are reader supported. When you purchase through links on our site, we may earn an affiliate commission. Also, as an Amazon affiliate, we earn from qualifying purchases.
When setting up a communal aquarium, it’s imperative that you keep all of its inhabitants happy and thriving. But, some fish are very picky about their water parameters, especially when it comes to temperature. Betta fish are one such example of a species that requires a specific warmth, which is imperative to their survival.
But can betta fish live in cold water? For a quick and short answer, no they cannot. They require a warmer temperature ranging between 74°F and 84°F. Anything colder than that has the potential to stress betta fish, which will lower its immunity and leave it susceptible to diseases, infections and even death.
Having said that, they can go as low as 72°F but you will have to take great precautions in acclimating them to this. Otherwise, they can suffer from temperature shock, which will definitely cause them to struggle.
Why Shouldn’t Betta Fish Live in Cold Water?
The number one reason why betta fish shouldn’t live in cold water is because bettas are tropical fish. Their native habitat is the warm and rushing waters of the Amazon River in South America. So, they do not like any amount of cold and it will cause them stress, which lowers their immunity.
For What Length of Time Can Betta Fish Be in Cold Water?
Temperatures above 72°F but below 74°F should be enough for a betta to live around three to six months. Anything below that is freezing for them and it will kill off the fish in a matter of days, if not within 24 hours.
What Is Cold Water Temperature Shock for Betta Fish?
When a betta fish is under stress and you notice the water is too cold, this condition is “temperature shock.” It refers to how the environment in the tank is far too low (or high) and is likely less than 72°F. Because bettas consider this freezing, it has the potential to create a host of serious ailments for the fish.
You could compare temperature shock for fish much in the same way you consider hypothermia in humans. Just like people, fish cannot handle living in water that’s too cold for their tastes and it will result in their organs shutting down along with fatal vital signs.
What Happens to Betta Fish in Cold Water?
In simple terms, bettas will be incredibly uncomfortable when in a cold-water environment. This, in turn, lowers their chances for survival because of the stress they experience from inadequate temperatures. Eventually, they will succumb to a bunch of undesirable diseases, infections and parasites.
If you don’t treat these issues promptly, they will die. Even if you do setup a quarantine tank and clear up their health problems, they can still return to a sickly state. This is because the main tank’s water isn’t warm enough for them. In the case a betta is sick often or for an extended time, they will not survive much longer.
First Signs of Temperature Shock: Lethargy
But, before stress and illness set in, there will by other signs and symptoms denoting the betta fish is beginning its downward spiral. Lethargy and inactivity will initiate this process and should be the first observable symptoms.
They’ll swim in a sluggish and lackadaisical manner while increasing their resting time. The betta fish may even spend more time toward the bottom of the tank or lying on its side because they have no will or strength to swim. If you see this happen, keep in mind that your fish isn’t dead but it’s definitely struggling.
A Coma Can Set In
In more severe cases, their stress due to cold water can result in a coma. Comas occur because the betta’s brain can’t get enough oxygen due to their slow, lazy movement. The best way to help them is to raise the temperature.
Metabolism Will Drop
Another sign that your betta is struggling due to the water being too cold is a drop in its metabolism. This means it will eat less, consuming less nutrients and minerals than it requires on a daily basis. When in a warm environment, they’ll be more active, eat more and have better digestion.
How Do You Prevent Betta Fish from Getting Cold?
The best way to keep betta fish warm and happy is by installing a heater with temperature controls, a solid thermometer and a strong, warm light. Make sure the range remains between 74°F and 84°F (about 23°C). If the temperature drops too far below 72°F, then you have to observe your fish for signs of temperature shock.
Another thing to consider when trying to keep betta fish warm is to check the general ambient temperature outside of the tank. If you’re home is at 70°F, this will affect the temperature within the tank and it will make things far too cold for your fish.
Avoid Severe Temperature Shifts
However, just because you install a heater doesn’t mean you should crank it up full blast. Severe shifts in water temperature, hot or cold, will stress the betta. So, you want to ensure you turn up the temperature gradually, one degree every other day or so.
What Should You Do When You Don’t Have a Heater?
In the event it will take awhile to acquire a heater or you simply don’t have one, you can always put a cover over the tank. Failing that, you could use an electric blanket, warm towels or even cardboard to encase the tank. Anything you can find to keep the glass warm on the outside from the activity within the tank will be ideal.
If you’re desperate, you could try lining the outside of the tank with tea lights. While these won’t be as effective as a heater, they’re better than nothing. Whatever you do, however, do not blast heat from a room heater, space heater or a blow dryer onto the surface of the tank.
Remember, betta fish can suffer from temperature shock from water that gets too warm too quickly as well. In the event you accidentally heat the aquarium too fast, you can add a few ice cubes or a frozen, unopened bottled water to cool things down. So, you have to be diligent in monitoring your thermometer for any drastic shifts.
What Else Could Cause a Temperature Drop in a Betta’s Tank?
If you have all the necessary accessories to keep your betta fish warm but the temperature drops in mysterious ways, something else is amiss. This could come from its location or water changes. However, equipment and/or power outlet failures could also be culprits.
Observe where the aquarium is in your house since this could be affecting fluctuations in the tank’s temperature. An aquarium that’s close to doors, windows or other entryways where air comes in can create a problem for your bettas. This is because the ambient temperature around the tank changes far too much.
This means you’ll have to move the tank to a more desirable location. Keep it away from outer walls, garages, basements and any place where temperatures tend to be unstable. Therefore, this is pertinent to those living in climates where there are distinct changes in temperature throughout the seasons.
Partial Water Changes
Sometimes, partial water changes can be the culprit of making the tank too cold. When doing a water change, let the water warm up before adding it into the tank. This will help avert severe changes in temperature and prevent betta fish from going into temperature shock.
Equipment or Power Outlet Failures
As always, check all equipment that provides heat to the aquarium to ensure that’s it’s working properly, including the power outlet. For instance, if there’s a short in your heater or power outlet, it means the tank is going without warmth for long periods of time and this can definitely cause the temperature to drop.
Is There Any Way for a Betta to Live in Cold Water?
While you want to avoid having a betta fish live in cold water, you can acclimate the fish slowly and methodically to cooler temperatures. But you will not be able to go lower than 72°F. Regardless, you can begin dropping the temperature over the course of several weeks, one degree at a time.
For every temperature drop, check the tank and your betta for signs of temperature shock. Look out for all the symptoms mentioned above: lethargy, lack of appetite, decreased metabolism, laying on its side or hanging out at the bottom of the tank. When you notice any of these, turn the temperature back up.
Having said all that, you should only attempt this if you absolutely must have the water on the cooler side. This would be due to keeping ammonia down or trying to find a happy medium temperature suitable for all species living in the tank. Other than that, you should never want to lower the temperature.