What is the Minimum Water Temperature for Guppies?

Some pets need more attention than others, and that’s especially true for fish. Guppies are no exception in this regard. Like any other fish, guppies have an ideal range of water parameters.

Whether we’re talking about water pH, water temperature, or water hardness, guppies have specific requirements that you have to meet. Any deviation from these parameters will lead to health issues or failure to thrive in your fish.

When you set up your tank, you have to try to imitate a fish species’ natural environment the best you can. A coldwater fish would obviously need a cooler environment to match its natural temperature needs. While guppy fish are sturdy and highly adaptable to different environments, they also have their own sweet spot where the magic happens.

It’s not enough to just keep your fish alive. If you want your guppies to grow big, colorful, and healthy, you’ll have to do some extra tweaking. But don’t worry! I’ll lay down everything you need to know. As a seasoned guppy owner myself, I always love learning something new about these little fish, and I’m passionate about sharing this information with new pet fish owners.

In this article, I’ll explain everything to do with guppy tank temperature. So, want to learn more about the ideal temperature ranges for guppies? Wonder what’s the minimum water temperature to grow healthy guppies? Well then, let’s get started!

Guppy Fish Natural Habitat

First, let’s talk about a guppy’s natural habitat. You can learn a lot about a pet’s needs and requirements when looking at their life in the wild. Guppies are tropical fish. In the wild, they inhabit the waters of the Caribbean and South America, and they’re especially found in hard and brackish water.

The ideal water temperature ranges between 72-82 °F (22-28 °C), although they can also sustain lower temperatures as well. In fact, they can even tolerate temperatures as low as 60 °F (15 °C).

As you can see, there’s a wide range of tolerated temperatures in guppies. These fish naturally enjoy higher temperatures due to their tropical habitat, but they can also live in colder water. So, what to do? Should you keep your guppies warm and cozy all the time? Or should you let them enjoy cooler temperatures? That depends.

As long as you don’t let the water temperature fluctuate too quickly or too often, there are benefits to both temperature ranges. Depending on your guppy’s age, health, and breeding, both warmer and colder water could be beneficial in different ways. And remember, even the same guppy fish has different needs sometimes. Your guppies’ needs might also change as they grow, so there’s no one-size-fits-all here.

Warm vs Cool Water for Guppies

So, what are the perks of either warm or cool water? Although guppies can tolerate both, it’s best to stick to either one or the other. Frequent changes in water temperature can stress your fish, leading to health problems. So, let’s see the benefits of warm vs cool water for guppy fish.

Warmer water encourages faster growth and breeding. If you want your guppies to grow bigger quicker, stick to the upper range of temperature. Warm water usually increases your guppies’ appetite and energy expenditure, both of which are great for healthy development. The downside to this is that guppies kept in warmer water tend to have shorter lifespans. An increased metabolism, faster growth, and constant breeding takes its toll on their body.

Cooler water increases guppies’ lifespan. Basically, colder water will have the opposite effect on your fish. Colder temperatures decrease guppies’ metabolism, which leads to slower aging, and thus a longer lifespan! But the tradeoff is that guppies kept in colder water will also grow slower and sometimes not as large. The choice depends on your goals. If you want to breed guppies for profit, warmer water is obviously the best choice. If you want your pet fish to live longer, then cooler water will help.

Is An Aquarium Heater Necessary?

As I’ve already mentioned, guppies prefer temperatures ranging from 72-82 °F (22-28 °C). Depending on the climate where you live, you might not need to use a heater year-round. However, temperatures can still fluctuate a lot, even during warmer seasons. At night, it’s not uncommon for temperatures to fall below 70 °F (21 °C), even in summer.

And that’s not even mentioning temperature drops that happen in winter. Even if you have a stable room temperature of 70-72 °F (21-22 °C) year-round, I’d say that’s still not enough to save you from using a heater. Water heats up slower than air, and every time you change the water in your aquarium, your fish might be exposed to sudden temperature fluctuations. It takes a lot of time for the water in your aquarium to reach room temperature, especially if you have a high-capacity tank.

You’ll definitely have to invest in an aquarium heater. This is the best and most safe way to ensure a constant, suitable water temperature for your guppies. You wouldn’t have to worry or guesstimate whether the water is warm enough for your fish. You’d also avoid temperature fluctuations which might stress your guppies.

Temperature During Water Changes

When I say keeping a constant water temperature is crucial, I mean it. This also applies to water changes. You don’t want to shock your fish when pouring back fresh water into the tank. So, the temperature of the new water should be as close as possible to that in the aquarium. You might have to measure the temperature of the fresh water before pouring it into the tank.

Try not to let the freshwater temperature fluctuate by more than 2-3 degrees Fahrenheit compared to the aquarium. For example, if the temperature in your aquarium is 73 °F, make sure the fresh water temperature is around 70-75 °F, but preferably as close to 73 °F as possible. If you don’t have one, a digital thermometer would be very useful when doing these water changes.

When you’re adding the fresh water back into the tank, remember to do it slowly! Your guppies need time to adapt to the new temperature and water parameters before your aquarium heater does its job. You wouldn’t like to jump straight into a pool full of cold water or into a hot bathtub and neither would your guppies.

Guppy Fish and Temperature Shock

You shouldn’t change the aquarium temperature by more than 2-3 degrees within a day. Even such small temperature differences can shock your fish and lead to death. This happens especially when the temperature fluctuation is negative.

Fish are cold-blooded creatures, so they rely on their environment to regulate their body temperature. When the water temperature drops suddenly, guppies’ bodies might have trouble keeping up. A drop of 2-3 °F within a few hours is enough to kill all guppies in your aquarium.

When the temperature drops below 60 °F (15 °C), guppies will most definitely die, as that’s below their tolerated temperature range. While 60 °F (15 °C) is the absolute bare minimum, it’s best to never let the aquarium temperature drop below 72 °F (22 °C), which is the optimal minimum temperature for healthy guppies.


Guppy fish can tolerate a wide range of temperatures, but they’re sensitive to sudden fluctuations in water parameters. You need to exercise great caution when completing water changes. While guppies can live in both warmer and cooler water, the key is to always keep the temperature constant.

Avoid any sudden change or drop in water temperature, and never let the temperature drop by more than 2-3 °F within a couple hours. As long as you manage to do respect these guidelines, your guppies should be just fine.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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