Aquarium Heating Tips

Aquarium heaters provide heat to your fish tank and help maintain a constant temperature level. Unlike humans, a relatively small temperature change of 10 degrees can kill fish. An undersized or cheap heater can potentially wreck havoc on your entire fish tank. Spend a few extra dollars on quality equipment and keep backups to minimize the chances of a disaster.

  1. Use the Correct Type of Heater

    • Choose a heater with watts equal to five times the amount of gallons in the tank. A 20-gallon tank requires a 100 watt heater, or two 50 watt heaters. Make sure your heater is saltwater safe if you have a saltwater aquarium. One type of heater is a heating cable system, which goes under the gravel and uses an electrical unit to evenly heat the tank. Unfortunately, a heating cable system is difficult to replace or repair because you have to dig up your tank. Hang-on heaters are usually cheap and imprecise. They have controls floating out of the water and a submerged glass tube. A quality submersible heater is the best choice for most fish tanks. They provide a consistent temperature, can be placed out of eyesight and have helpful controls.

    Have a Backup Heater

    • If your water tank heater breaks, you ideally want to immediately replace it. Many fish are sensitive to temperature differences and can quickly die when it becomes several degrees colder. Avoid emergency trips to the pet store by having a backup heater available. If your heater breaks in the middle of the night or on a holiday, your fish could be in trouble by the time you can get a replacement.

    Use Two Heaters

    • Large tanks benefit from having two heaters in the water. Place the heaters on opposite sides of the tank for a more even distribution of heat. If one heater breaks, you at least have the other one still going. For example, you can use two 100 watt heaters in a 40-gallon tank instead of a single 200 watt heater.

    Use Two Thermometers

    • Spend a few extra dollars and purchase a quality thermometer unit with an alarm feature that warns you of temperature changes. If your heater malfunctions, you want to know before the next morning when you could find a tank full of dead fish. Thermometers are not always reliable and it's best to have at least two. Use one that floats in the water and another that hangs on the inside of the glass.