What Size Heater Do You Need for Your Fish Tank?

If a fish tank is in a heated room, the wattage can be 2 or 3 watts per gallon.

The general rule for selecting what size heater you need for a fish tank is called the "5 watts per gallon rule." However, this is a flexible rule depending on what is in the aquarium.

Considerations

Aquariums are often kept in heated rooms. In this case, two or three watts per gallon would be appropriate if the tank is 30 gallons or less, according to "Saltwater Aquarium."

Contents

Aquariums are often full of more than just water and fish. Gravel, decorations and equipment can take up room in the tank. This is another case where a heater that emits two or three watts per gallon would be okay, according to "The Everything Aquarium Book."

Warning

Some species of aquarium fish, especially saltwater and brackish water fish, do not need their tank's water heated. Always be sure to research a fish's needs and temperature preferences before purchasing or adopting.

References

• "Saltwater Aquarium"; Gregory Skomal; 2000.
• "The Everything Aquarium Book"; Frank Indiviglio; 2006.
• The First Tank Guide: Heaters

Resources

• Aquarium Life: Aquarium Heater Wattage Calculator
• Fish Channel
• Aquatic Community Tropical Fish