Fish require proper water temperature control to stay alive and healthy in the fish tank. You must keep in mind the necessary water temperature differs according to the type of fish you have. There is no need to keep the water at a high temperature if you have freshwater fish. On the other hand, if you have tropical fish, the water should be warmer and in the case of saltwater fish the temperature should be even higher yet.
Step 1 - Ask a Pet Store Assistant
If you do not know the right water temperature for your fish, ask a pet store assistant for information. For such freshwater fish as goldfish, the temperature should be about 52 to 65 degrees F. On the other hand, the temperature needs to be about 75 to 80 degrees for guppies and other tropical fish. Last but not least, clownfish and other saltwater fish prefer a water temperature of about 78 to 83 degrees F.
Step 2 - Install a Heater
You'll need to buy and install a fish tank heater to keep your fish comfortable in the water, especially if you have saltwater or tropical fish in your fish tank. Ask a pet store worker for information about the correct size and wattage of the heater.
Step 3 - Adjust the Heater
Adjust the temperature of the heater to heat up the fish tank properly. Keep in mind that you need to raise the temperature by two to three degrees if you want the fish to breed. Raising the water temperature will also help to cure ick, a common disease in which white spots develop on the bodies of freshwater fish. Freshwater ick can kill your fish if you do not treat it immediately. In case you have multiple fish species living together in the aquarium, it will be better if you keep an average water temperature.
Step 4 - Install a Mini Fan
Purchase a mini fan and install it on the side of the fish tank. Make sure the mini fan is equipped with a clip-on attachment and remember to point it towards the surface of the water when installing it. The mini fan will be responsible for cooling the fish tank in case the temperature in the room becomes very hot. Remember that a mini fan installation will accelerate the evaporation process of the water in the fish tank, therefore make sure that you keep a bucket filled with aquarium-ready water ready at all times.
Step 5 - Install a Chiller
If you do not want to install a fan in your fish tank, you can buy a chiller instead. But you need to be cautious and keep in mind that a chiller costs hundreds of dollars, much more expensive than a mini fan. The price depends on the size of the chiller as well. If you are a professional aquarist or fish keeper, chillers are the most appropriate cooling equipment for your fish tank.
If you want to lower or raise the temperature of the water, do this very slowly. Change the water temperature one to two degrees at a time. A sharp change can stress and even kill your fish.