Like other types of tropical fish, guppy fish are accustomed to living in warm waters. However, they can also survive in cooler water for short periods of time. Though, they are prone to develop diseases increase the longer they are exposed to cooler temperatures.
Do you need a heater for you guppy fish tank? Yes! You need to heat the water for your guppies, unless you live in a tropical climate, where the temperature does not drop under 68 °F (20 °C). Even then, a water heater is still a good idea to keep the temperature constant.
What Size Heater Should I Get?
It can be difficult to determine what kind of heater to get for your guppy tank. But, 5 watts per gallon of water volume is ideal. Here’s a simple table to help you decide which water heater to get for indoor aquariums, where the room air temperature is set to 70 °F (21 °C).
|Tank Size||Heater Wattage|
|5 Gallon / 20 Liter||25 W|
|10 Gallon / 40 Liter||50 W|
|20 Gallon / 80 Liter||100 W|
|25 Gallon / 95 Liter||125 W|
|40 Gallon / 150 Liter||200 W|
|50 Gallon / 190 Liter||250 W|
|65 Gallon / 250 Liter||2 X 200 W|
|75 Gallon / 285 Liter||2 x 300 W|
Indoor Guppy Care
Guppies can survive at a water temperature of 70 °F. The only problem is that the water in your aquarium will not have the same temperature as the air.
The water heats up slower than air and also cools at a slower speed. Thus, it’s a good idea to get a water heater to keep the temperature at an optimal range at all times.
Outdoor Guppy Care
For those of us living in tropical regions, its ok to keep your guppies outside. The sun serves as a heater and will keep the temperature in the tank, tub, etc. constant.
At nights, the temperature slowly cools but not so much to put the fish in danger. The only thing to look out for is those extra hot days where you may need to provide some shade for your guppies to prevent overheating.