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Do Guppies Need a Heater? 6 Guppy Temperature FAQs and Answers

The guppy, also known as rainbow fish and million fish, is a tropical warm-water fish. They are one of the most popular freshwater tank fish species.

Guppies are pretty small in size and look very attractive, particularly the males. They are colorful and have a green and deep yellow color scheme. You may also find red, silver, blue, and black guppies, but these are extremely rare.

It is not only because of their beauty that most people prefer them, but they are also easy to take care of. Though you do not have to do much, one thing you need to give importance to is the water temperature.

Remember, they are warm water fish and so the water temperature has to almost always remain fairly warm.

This gives birth to a question, do guppies need a heater?

Well, continue reading and you will discover your answer.

What Is the Ideal Guppy Temperature?

Guppies require the water temperature to be around 74- and 82-degrees Fahrenheit when in the wild.

As far as the ideal guppy temperature in an aquarium is concerned, they will be happy if it ranges between 70 to 80 degrees Fahrenheit (74 to 82 degrees is still the best though).

They can withstand slight changes in temperature. But if you want them to healthy and happy you need to try to maintain the recommended temperature range always.

What Will Happen If the Water Gets Very Cold?

Slight dips in temperature are okay but if the water gets too cold it can cause havoc.

If the water temperature goes below 68-degrees Fahrenheit the guppies will become inactive and sluggish. They will not even breed and will eat less.

In case the temperature goes below 60-degrees Fahrenheit your guppies will not survive for too long.

So, Do Guppies Need A Heater?

Yes is the answer. You must place your guppies in an aquarium that has a good quality heater. This is not only because the water temperature should be between 74- and 82-degrees Fahrenheit. It is also important for the temperature to remain consistent.

If there is too much fluctuation then your precious guppy can experience a lot of problems. It can go to the extent of being life-threatening.

The sole way to always keep a constant temperature in your tank is by using a heater. You may say the temperature where you stay is constantly hot.

But even then, you cannot be a hundred percent sure if your tank too always receives the desired constant heat.

In case the weather gets cool just for a few days, the temperature in your tank will drop. You might not even realize it, but your guppies will have to suffer. So, a heater is an absolute must.

Do Baby Guppies Require A Heater Too?

Yes, baby guppies or fry as they can be called require a heater as well. In fact, they need the temperature to be a little warmer than what is good for the adults.

They cannot hold body heat for too long because of their little size and a heater then comes to their rescue.

So, remember, an adult guppy needs a heater and their babies need it even more.

What Type of Heater Can You Use for Your Guppy Tank?

Now that you understand the importance of a heater for your tank you also need to find the right one. There are basically four kinds of heater that you can use for your guppy aquarium.

It includes a substrate heater, external inline heater, submersible heater, and hang-on heater. We shall learn about each of these in brief.

Substrate Heater

If your tank contains guppies and plants then the substrate heater is the best choice for you. It contains heating coils that will be attached below your substrate. Once activated, this will keep the water warm.

The substrate heaters provide more uniform heating. They are also not visible since you will attach them below your substrate.

External Inline Heater

Filter heaters are a good choice for large tanks. They provide proper heating and thus is preferred by many. The way they are installed they remain invisible and thus will not come in way of the beauty of your tank.

Submersible Heater

Submersible heaters are made of durable plastic or glass. The glass ones are quite fragile and need gentle handling which is not a problem with the plastic heaters.

You have to make sure to keep the submersible heater below the water line for it to work.

Hang-On Heaters

These are extremely popular because they are cheap and come equipped with many starter tank kits.

When you use a hang-on heater the control has to be kept above the waterline. Such heaters are not a great choice for salty tanks because of corrosion and electrical shock.

Should You Invest in A Spare Heater for Your Guppies?

Heaters are just electronic devices and just like other devices they too might suddenly stop working. If the water temperature is then left uncontrolled it can prove to be very bad for your guppies. This is why you must also opt for a standby heater.

The spare heater need not be anything pricey as you will only be using it until you get your main heart repaired.


So, your question, do guppies need a heater, is definitely answered by now. You also have learned about the ideal guppy temperature and the various heaters that you can use in your tank.

But, there is one very important thing you need to remember. Though proper heating is essential for guppies, excessive heat too can be bad. If the water gets too hot you will notice the guppies will begin swimming erratically and rush around. This is because they will have more energy than they need.

Though this sounds pretty good it is actually disastrous. It will cause great stress and their immune system will get weak. There thus will be increased chances of them falling ill.

So, you have to be very, very careful. You need to make sure that you set your heater in a way that the water temperature always remains within 74 and 82-degrees Fahrenheit.

Then, you will have nothing to worry about. Your guppies will always be healthy and swim around joyfully.

Aaron Boyd
Aaron Boyd

Hello, I’m Aaron Boyd, the proud owner and author behind Aqua Movement. I hope my article was able to answer your questions. If you want to learn more about me, click the home icon above.

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