Guppy Fish Maximum Water Temperature

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In aquariums, guppy fish thrive best in environments where the temperature is controlled, where sudden changes are not a risk, and the stability of water parameters is guaranteed.

If it’s your first time ever keeping guppy fish, you’re probably researching their water requirements and the ideal temperature range for guppies.

Guppies are tropical fish that like warm water and live in warm waters in the wild, but which is the maximum water temperature for keeping guppies? And what else should you know about guppy aquarium temperature conditions?

In this article, I discuss the water temperature requirements of guppy fish, whether they need a heater or not and give you a few examples of fish that enjoy warmer waters.

Guppy Maximum Water Temperature

Guppy fish will tolerate water at up to 90 °F (32 °C), but never for a prolonged time and only if the water is well aerated because the warmer the water, the lower the oxygen level in it.

And oxygen is extremely important for fish too, especially guppies that enjoy well-oxygenated waters.

However, in the case of some guppy diseases, actually raising the temperature to 86 °F-90 °F will shorten the recovery period and help your guppy fish heal faster.

Usually, guppy disease remedies that recommend raising the temperature will recommend doing it for a week or so, and not longer.

I also wouldn’t recommend going anywhere above 90 °F, because water that warm can no longer hold oxygen, and you risk depriving your fish of valuable oxygen.

Even when you raise the temperature up to 90 °F make sure to keep the water well circulated and aerated by installing an air pump into your tank to help drive more oxygen into the water.

The air pump should not be noisy and should consider the size of your aquarium, so it can efficiently circulate the water.

You should also perform regular water changes to dilute toxins and replenish the water in your guppy aquarium.

The takeaway here is that any temperature outside the ideal temperature range for guppy fish will create problems and eventually result in their death.

Guppy fish tanks also require a filter system, which has the benefit of clearing the water of debris and decaying plant matter, aiding in the removal of toxins.

Do Guppies Need a Heater?

We’ve established that guppies do need a filter system and preferably an air pump too, but do they also need a heater? Or they’ll be fine without one?

It depends. If you’re raising guppies in a tropical region of the world, with high temperatures all year round, you’re fine without a heater whether you’re keeping your guppy fish indoors or in outdoor ponds.

This, of course, if the temperature does not drop below 68 °F (20 °C) in the winter. If it does, you need a heater even if you’re keeping your guppy fish indoors.

If you want to keep guppies in outdoor ponds and live in a temperate climate, you can still do so but only during late spring and during the summer.

Even if your house is well heated, the air temperature in your home may not always be stable, and guppies need stable temperatures.

Fluctuating temperatures in guppy tanks can become a huge problem and can cause diseases and even death.

You may think that simply heating your room to a comfortable temperature is enough. Unfortunately, air warms up faster than water, and the water in the aquarium will not be as warm as the air temperature in your home.

In this context, you will need a heater for your aquarium not only to warm the water to the required temperature range for guppies, but also to keep the temperature stable.

When it comes to aquarium heaters the choices are many, but beyond quality and pricing, you should also pay attention to picking the right heater size to make sure water is being warmed efficiently.

So, here’s a good rule to go by 5 watts per gallon of water volume. By following this rule, you can ensure that the water in your aquarium is kept at the required temperature.

Undersizing the heater will lead to inefficiencies as the heater won’t be able warm the water to the required temperature.

With all this talk about the ideal temperature or the optimal temperature range for guppies, let’s see which is the range that’s best for guppy fish?

Ideal Water Temperature for Guppies

Guppy fish should be kept in water that’s in the 72-82 °F (22-28 °C) temperature range. Falling below or above this range either suddenly or for prolonged periods opens the way to health issues.

So, if there are fluctuations in the temperature or if guppy fish are kept at temperatures outside of their comfort zone, they’ll become sick to the point where they can even die.

If you don’t want to invest in an aquarium heater for your guppy fish, you should consider fish that enjoy colder water temperatures such as goldfish, zebra danios, pearl danios, green barbs, etc.

These fish can be kept or can easily adapt to aquariums without a heater.

If you’re willing to invest in an aquarium heater, guppies are not the only ones that enjoy warmer water.

There are many other fish that have a preference for warmer water.

Fish that Can Tolerate Warmer Water

The most common fish that either enjoy warmer water or can adapt to warmer water temperatures include:

– Swordtails

Swordtails are interesting fish that aren’t very demanding. They enjoy water with temperature ranging between 72°F- 78°F (22 to 26 °С) and should be kept in spacious tanks with lots of swimming space as they grow quite large (4 inches on average).

The female to male swordtail fish ratio in the aquarium should be 1:3, that is one male to 2-3 females, otherwise female fish will get stressed out.

Swordtails are generally peaceful fish, although they can be aggressive towards other males of their own species, so make sure to be on the lookout for signs of aggression.

If you have a smaller aquarium, definitely don’t keep more than one male with females as they’ll both stress out females and compete with each other for female swordtails.

– Platies

Available in multiple colors and patterns, platies are unpretentious and highly lovable fish that will feel best in water that’s between 72°F- 78°F (22 to 26 °С).

Platies are extremely peaceful, and they can make great tank mates for a variety of peaceful freshwater fish.

Platies enjoy dense vegetation in their aquarium and thrive on a varied omnivorous diet. Pick a high-quality flake food and add vegetables and live or freeze-dried foods to their diet.

They make an excellent choice for beginner aquarists whether in a species-only aquarium or a community fish tank.

– Mollies

Molly fish are extremely popular in the aquarium trade and most aquarists have kept molly fish at some point in their lives.

They’re peaceful, easy to please, and they’re available in a lot of varieties, not only color varieties but also patterns, shape and size varieties.

Mollies are active fish that enjoy being kept in a shoal, which should be predominantly female as males will otherwise chase and stress out females.

Molly fish are tropical fish and enjoy the water in the 72-78°F range. Just like guppies they require stable temperature and need a heater in their aquarium.

– Angelfish

Angelfish are unique, slim and tall-bodied fish that feature long, flowy fins. These fish grow quite big and because of their peculiar body shape they need large, tall aquariums.

Angelfish require a heater in their tank and the temperature should be kept between 76-82°F. They should be kept with fish that aren’t small enough to fit their mouths and aren’t fin-nippers.

Angelfish do not give birth to live fish, instead they lay eggs and hatch the eggs themselves. Unlike live-breeders, angelfish are actually recognized as fish with good parental skills.

Despite not being suited to be kept with aggressive fish, angelfish themselves can become aggressive too, especially when breeding.

These are just some of the fish that enjoy warmer water that you should consider if you have an aquarium with a heater that allows you to keep stable temperatures.

Remember that any fish that are kept at temperatures outside of their preferred range will have issues and few fish can adapt to different conditions.


Even though guppies thrive in warmer water, they do have a preferred range that should be respected.

The maximum temperature they can tolerate is up to 90 °F if it’s for a short period and especially when applied for therapeutic purposes.

A quality aquarium heater will help you keep the water temperature stable and between 72-82 °F, which is the ideal interval for guppy fish.

I hope my article has answered your questions about the requirements of guppy fish when it comes to temperature and I have given you a few ideas of other fish that also enjoy warmer water.

Whenever you’re picking out fish for a community aquarium, make sure to always see if their water requirements (temperature included!) match up.

Updated: January 8, 2022

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