Things You'll Need
- Aquarium thermometer
- Aquarium heater
Instructions
Research the temperature needs of the fish you are keeping. Most fresh water tropical fish need a temperature of 77 to 83 degrees, while saltwater tropical fish need a temperature that is 76 to 82 degrees.
Install an aquarium heater and thermometer in the aquarium. See what the temperature of the water currently is and set the heater accordingly.
Watch the tank for 24 hours for fluctuations. Even if the fluctuations are within the safe range, huge changes in temperature can kill or stress fish.
If the temperature is dropping quite a bit at night, but staying within the safe range during the day, increase the temperature on the heater. Monitor the tank to make sure the temperature is not getting too hot after making this adjustment.
If the tank is getting too hot, place a fan near it that will blow across the surface of the water. Keep the room cool where the fish tank is.
Keep the fish tank out of direct sunlight. This can heat the water quite a bit and create dangerous temperature changes for fish.