Do Guppies Need A Heater To Survive?

Guppies are humid kinds of fish, and they love warmer water. Although guppies can endure in lower temperature water, the chances of emerging types of diseases are really on a high side. So do they need a heater?

Guppies do not need a heater to survive, but they will not thrive in colder water. The ideal temperature for guppies to thrive in is 72-82 °F (22-28 °C)  It is recommended to use a heater to maintain your water temperature. 

Do Guppies Need A Heater To Survive

The best way to maintain a water temperature of around 72-82 °F (22-28 °C) is to use an aquarium water heater.  I can recommend the FREESEA Aquarium Fish Tank Submersible Heater from amazon.

Guppy Aquarium Heater Size Manual

If you need to sum up the wattage your aquarium needs, use the below guide: 5 watts gallon of water volume. The table below is for in-door tanks/aquariums and room temperature, in which air is set to 70 °F (21 °C).

Tank Size Heater Wattage
Five Gallons / 20 Liters 25 Watts
Ten Gallon / 40 Liters 50 Watts
Twenty Gallon / 80 Liters 100 Watts
Twenty-five Gallon / 95 Liters 125 Watts
Forty Gallon / 150 Liters 200 Watts
Fifty Gallon / 190 Liters 250 Watts
Sixty-five Gallon / 250 Liters 2 X 200 Watts
Seventy-five Gallon / 285 Liters 2 x 300 Watts

 With this arrangement, you will have the ability to heat the tank/aquarium water up to 75 °F (27 °C).

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Keeping Guppies In-Door

Is there a need for the heater if you preserve your aquarium in your home, which is already heated? If you live in a kind of weather, where it is necessary to warm your home in the winter, possibly you will fix a temperature of 70 °F (21 °C).

Guppy fish can stay at a water temperature of 70 °F. The only issue is that the water of your tank will not read the same temperature as the air because water heats up slowly than oxygen (air), and also cools at a lesser speed. I’ve noticed in a room, where the air hotness is set to 70 °F, the water will heat up to around 64-66 °F (18-19 °C). This is hazardous to your guppy fish.

If you are continuing with these measurements in the winter, you need to obtain a heater for your guppies. The table that is shared above will explain all you need to know about the setup. The table is accurate for keeping a constant water temperature of 74 °F (23-24 °C) in a 10-gallon guppy tank.

Keeping Guppies In Tub or Pot

If you stay in a tropical climate where the temperature in the winter does not fall below 68 °F (20 °C), you can keep guppies separate from an aquarium or tank. There are some cities like Hawaii, where you can keep guppy fish outside the tank or aquarium in a pot or bathtubs all year due to the climate of the town. It is recommended, you know the environment you live and what will be a perfect atmospheric condition for your fish there. The temperature in Hawaii does not go below 68 °F (20 °C) anytime in the year; if you live in this kind of environment, there is no need for using the heater as you already keep your guppies in a tub.

You can still breed and nurture guppies outside in tubs or ponds, even If you live in a region where the temperature drops below the freezing level. The most essential is to set up your bathtubs or pond during the early spring when the temperature does not go below 64 °F (18 °C).

During the day the sun will warm up the water in the pot/tub/pond adequately to be nontoxic for your guppy fish while in the night, the water temperature will not fall so meaningfully, because water cools down slower compared to air.

During the warm summer, you might want to craft some shade around the tub so that you can prevent overheating of the water.

Can You Keep Guppies In Cool Water?

Once the temperature starts falling in the pond, you should prepare to move your guppies back to the tank or aquarium where you can introduce heater, or you can still introduce heater to your pond/tub/pot. To a certain level, you can use heaters to make sure the water temperature of the pond is at your preferred level, but it is very inefficient, according to most users.

If you live in a place with an Inland climate, and in the winter, the temperature often drops under freezing rate, then you might still be able to keep the guppies for months. 

In the winter, all tanks/aquariums should be heated with one or more tank heaters.

Do You Need A Heater For Your Fish Tank?

If you have humid fish that need warmer water that is in standard room temperature, then a heater is indeed required.

A heater is even more so of a necessity in a small tank, which is more exposed to temperature changes due to the low water volume.

These changes in temperature are stressful to your fish and can cause infection and even death to your guppy fish.

A tank/aquarium heater will help preserve the water temperature stable and keep your fish healthy.

How to Select A Heater For Small Aquarium?

When selecting a small aquarium heater, there are a few factors to put into consideration, they are:

i) The size of your aquarium; The volume of water in the aquarium matters a lot. 

ii) Temperature; According to the guidelines explained here, know how to measure the room temperature; this will determine if you need a heater or not.

iii) Know the amount of heat that’s necessary in your aquarium/tanks.

The capacity of small aquarium heaters is measured in watts while the more the wattage, the more powerful the heater. For instance, a 50 W heater is adequate for a ten-gallon tank/aquarium.


Expectantly, this piece has aided you to agree if you need a heater for your guppy fish or not. If you need more explanation about using a heater in your aquarium or you want to share your experience with us, then feel free to share your thoughts through the comment section. 



Hello, I'm Jason. I'm the guy behind I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.

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