Do Guppies Need A Heater In Their Tank? | Fish Camp Rehab

Do guppies need a heater in their tank? In this article, you’ll learn if it is essential to have a heater for your tank and numerous other valuable details!

Guppies are tropical fishes and they prefer warmer water temperatures. Although they can live in cooler waters, the likelihood of developing certain kinds of diseases is extremely high.

Alongside knowing whether guppies require heaters to keep them warm, or not. You’ll discover these things:

  • What happens when water becomes too cold or hot?
  • What is the ideal temperature for guppies to be able to live (and most importantly, thrive)?
  • How long will they last without the aid of a heater?
  • What happens when the temperature fluctuates rapidly?
  • The best place to put the heater.
  • What size heater should you put in your tank?

Continue reading to find out more!

Do Guppies Need A Heater?

Absolutely it is recommended to put your guppies into an aquarium that has an electric heater! This isn’t only because the water has to be kept between 74 and 82 degrees. It’s due to the fact that the temperature needs to be stable as well.

If temperatures fluctuate too much then your guppy may be afflicted by a variety of issues that could pose a life-threatening threat.

The only way to keep an even temperature is by making use of the heater. If the area in which you reside is always hot, this could not be the same as your fish tank.

For instance, a windy day or two cold days can dramatically lower the temperature of your tank. It also takes longer to warm in comparison to the atmosphere surrounding it.

What Temperature Do Guppies Need?

Guppies must be kept in water that ranges from 75-82degF (23-28degC). Although they are able to be kept at temperatures a small amount lower and slightly higher, this isn’t the optimal temperature for them and it may weaken their immunity which makes them more prone to illnesses.

It’s crucial to know this in order to know if Guppies require heating or not.

Guppy Aquarium Heater Watt Size Guide

Do Guppies Need A Heater In Their Tank
Do Guppies Need A Heater?

If you’re looking to buy heaters, you’ll want to ensure you have the right wattage to use them. This guide will inform you about the various power levels you’ll require, based on the size of your tank. is.

If you’re trying to figure out the power you require you can use the basic principle of 5 Watts for every gallon of the volume of water. The table below is intended for indoor aquariums where the temperature in the room is set at 70 degrees (21 degrees Celsius).

Tank SizeHeater Wattage
5 Gallon / 20 Liter25 W
10 Gallon / 40 Liter50 W
20 Gallon / 80 Liter100 W
25 Gallon / 95 Liter125 W
40 Gallon / 150 Liter200 W
50 Gallon / 190 Liter250 W
65 Gallon / 250 Liter2 X 200 W
75 Gallon / 285 Liter2 x 300 W

By using this method it is possible to heat the aquarium water as high as 80 degrees (27 degrees Celsius).

I have used and highly recommend theEheim Jager aquarium heater (on, which has the ability to set a thermostat. They are extremely reliable. I’ve used them on multiple occasions and they have not been faulty. I have one, that I’ve used for more than 8 years and it still functions flawlessly.

EHEIM Jager Aquarium Thermostat Heater 75W
  • Fully submersible
  • Thermo safey control protects against running dry
  • Will automatically turn off when water level dips too low
  • TruTemp dial recalibrates the heater for precise temperature...
  • Made of shock resistant and shatter proof glass for fresh or marine...

Last update on 2024-07-11 / Affiliate links / Images from Amazon Product Advertising API

If you follow this advice, you’ll always be secure with the knowledge that you’ve found the proper dimensions of the heater that will fit in your tank!

My Second Recommended Heater

If you don’t have a heater, I recommend Fluval M Series Heaters. Although they’re not the most expensive available, however, they’re what I’ve used in my previous aquarium and have had great results. Fluval is a highly reliable brand, and you don’t be worried about them breaking or harming your fish.

Fluval M 200 Watt Submersible Heater
  • Submersible heater provides exceptional performance and unsurpassed...
  • The heater also includes an exclusive mirror technology that reflects...
  • Sleek and compact
  • Quality heater made in Europe using superior components and...
  • For fresh and saltwater tanks

Last update on 2024-07-11 / Affiliate links / Images from Amazon Product Advertising API

Where Should You Place The Heater?

When you place your heater when you place it, try to keep it near proximity to the filter if possible. The filter will aid in the circulation of warm water through the tank so that the temperature will be equally spread out.

If you do not place it close to it, the filters might end up having an area of your tank that is warmer in comparison to the opposite.

In certain situations, there are times when you’ll require several heaters inside the tank (for larger tanks.) In this situation, you’ll need to place one heater next to the filter and another heater to the side opposite the first one, so that the heat is distributed equally.

What Happens If The Water Gets Too Cold?

If you do not warm the tank, and the water gets extremely cold, the situation could be disastrous for your Guppies.

The first indication of a drop in temperature that affects your guppies will be that they’ll appear tired and unmotivated. It’s because they’re cold-blooded. Therefore, their body temperature is in tune with the environment.

This strain on their body is also a reason that they do not desire to eat, which can make it more difficult for them to maintain their immune system.

In this stage, they’ll usually get closer to their tank’s bottom. If you have fish that are territorial there, it might create trouble and lead to your Guppies being attacked.

If the temperature does not rise and you have a weak defense system, there’s a higher likelihood that your pet will develop an illness. Swim bladder disease and dropsy are likely to become more prevalent (and much more likely to cause death).

What Happens If The Water Gets Too Hot

There’s more than just cold water that you must be concerned about but hot water too. (Although the odds for the water tank to overheat are not as likely).

If your tank is excessively hot you’ll notice your guppies begin to swim in a flurry and scurry around. This is due to the fact that they’ll have more energy to use.

Although this may seem to be a good thing, in reality, it’s going to cause a lot of harm to the people who are affected. They’ll be stressed out, which will weaken their immune system, and increase the likelihood of them becoming sick.

It’s actually an easier task to cool down your tank than to heat it up. It’s as simple as adding chilled, conditioned water into the aquarium (not overly) and then removing the lid of the tank or letting a fan blow on it!

What Happens If The Temperature Changes Too Suddenly?

In the event that you’re still keeping them in a room without a heating system, An abrupt change in temperature is likely to occur, and it’s also the most hazardous thing of all three.

If the temperature drops abruptly there are several possibilities for occurring.

Temperature Shock

Temperature shock occurs when your guppies enter shock because of a sudden change in temperature. It’s more likely to occur when you’re changing your water, but it could happen anytime there isn’t an electric heater within the tank.

If your puppy goes into temperature shock, it may be dead in just minutes. If they don’t, they could be in an induced coma that could cause permanent harm to them.

Respiratory Problems

In addition to the effects of temperature shock, they’re also significantly more likely to develop respiratory ailments. This is more likely to occur when temperatures rise too high (which could happen in the event that you’re relying on external resources to warm your water tank.)

When water becomes too hot it loses oxygen which makes it more difficult for your Guppies to breathe. If it is left for too long, the situation could turn fatal.

Don’t Rely On The Heater To Tell The Temperature

Additionally, the majority of heaters inform you of the temperature they are at, however, it’s not a good idea to rely solely on this. You must also utilize an instrument to ensure the temperature of your tank is constant. I prefer my Marina Floating Thermometer since it’s affordable and reliable!

Marina Floating Thermometer for Betta Fish Tank with Suction Cup, Aquarium Thermometer, 11201A1
  • Easy to read floating aquarium thermometer with suction cups
  • Includes a safety zone indicator appropriate for most tropical fish
  • Equipped with suction cups to attach to the side of your fish tank
  • Ensures your aquarium is at the proper temperature
  • Thermometer is 4.25 inches tall

Last update on 2024-07-11 / Affiliate links / Images from Amazon Product Advertising API

Keeping Guppies In-Door

Do you require an electric heater if you have an aquarium inside your home that is heated?

If you reside in a climate where you require heating your home in the winter months, it is likely that you will choose a temperature of 70 deg (21 degrees Celsius).

Guppies are able to survive in temperatures of 70 degrees Fahrenheit. The only issue is that the water in your aquarium isn’t going to be at similar temperatures as air. The water’s temperature rises faster than air and cools down at a slower rate.

I’ve noticed that in a space in which the temperature of the air is set at 70 degrees and the water is heated at 64-66 degrees (18-19 degrees Celsius). This can be dangerous for your fish which is a guppy.

If you’re living with these guidelines in winter, you should find a heater for your puppy. I am using my Eheim Jager 50W aquarium heater. It is ideal for maintaining the temperature of my water constant at 75 deg (23-24 degrees Celsius) in my 10-gallon Guppy tank.

EHEIM Jager Aquarium Thermostat Heater 50W, Black
  • Fully submersible
  • Thermo safey control protects against running dry
  • Will automatically turn off when water level dips too low
  • TruTemp dial recalibrates the heater for precise temperature...
  • Made of shock resistant and shatter proof glass for fresh or marine...

Last update on 2024-07-11 / Affiliate links / Images from Amazon Product Advertising API

Keeping Guppies in Pond or Tub

If you reside in a tropical area, where the temperature during the winter months does not fall below 68 degrees Fahrenheit (20 deg C) you can keep guppies outdoors in a tub or a pool.

You are able to cultivate and rear guppies in ponds and tubs even if you reside near a place where the temperature is below freezing. It is important to prepare your pond or tub at the beginning of spring, the time when temperatures don’t decrease below 64 degrees F (18 degrees Celsius).

In the morning, the sun’s rays will heat your pond’s water enough to make it safe for your fish that are guppy. In the evening the temperature of the water is not likely to drop as much as the water cools faster than air.

In summer’s hot temperatures, it’s a good idea to shade the pond in order to prevent overheating the water.

When the temperature begins to drop during the autumn, think about moving your guppies indoors. To some extent you could make use of heaters to maintain the temperature of the pond at the desired temperature, however, it’s not very efficient in my experience.

I reside in the Continental climate, which means that during winter, temperatures often drop below the freezing point. However, I’m able to keep guppies outdoors in my garden for 7 to 8 months without the need for heating.

In the winter, all my tanks get heated by one or more heaters for my aquariums.


Does Guppy Fry Need A Heater?

Like the guppies, guppy fries are going to require a heater to keep them warm, too. The temperature of your guppy fry needs to be set between 76 and 80 degrees F.

What Temperature Can Guppies Tolerate?

Although you shouldn’t allow them to live in such conditions they can be tolerant of conditions as cold as 70 degrees. A guppie can last for a short period of time in temperatures that are as low as 60degF

Can Guppies Live Without A Heater?

YES! It is necessary to warm the water to make a puppy if you are in a tropical area, where temperatures do not fall below 68 degrees Fahrenheit (20 degrees Celsius).

What Temperature Is Too Cold For Guppies?

Guppies can be described as tropical fish utilized to supplement warmer weather. This means they shouldn’t be kept in water with temperatures less than 60 F (16 C). Guppies are able to survive when temperatures drop to that low, but they aren’t designed to be in water that is cold.

What Do Guppies Need In Their Tank To Survive?

As with many livebearers, Guppies have pH levels of 7.0 or higher. They also prefer hard water that has high levels of magnesium, calcium, and other vital minerals. If you’re a resident of well water that has an elevated pH level, then you’re bound to be one of the top breeders of guppy ever.

Can Guppies Live Without A Filter And Heater?

Although technically it’s possible for guppies to live without filtering, however, it is recommended to have a filter installed inside your fish tank.

Do Guppies Need Light At Night?

No, guppies don’t need light at night. Guppies require darkness to sleep and relax properly. The aquarium lights on all of the time can cause poor sleep or even death. The average puppy needs up to six hours of sleep per day, so it is recommended to switch off the lights at the same time.

Can Guppies Live In Tap Water?

Guppies are a freshwater species of fish however, you may not be able to drink water directly out of the faucet. Chlorine is an issue for fish, which is why it is recommended to use water that is dechlorinated. It is possible to purchase water for your tank or you can make use of tap water and keep the container covered for up to 24 hours.

Final Thought

So, do guppies need a heater? You are aware that guppies require heaters and you must be equipped with the information you need.

The most important thing to remember is that you should not allow the water to get too cold or hot. Also, you shouldn’t let the temperature inside the tank vary too dramatically!

If you’re planning to put an electric heater inside your tank, you must pick a reliable model like the Fluval M Series. Fluval M Series.

In the event that you require multiple heaters inside the tank, place one near the filter, and the other to the other side in order to effectively disperse the heat.

Also, don’t depend on the heater in your tank to inform you of the temperature You should also include the thermometer!

Hope this article provided you with the knowledge to determine if you require an electric heater for your fish or not.

If you have questions or would like to add anything to this post, feel at ease to post a comment below.

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Dibyajyoti Bordoloi is the creator and author of, a third-generation experienced fish keeper and owner of a successful pet breeding farm. He is also a member of the Center for Wildlife Rehabilitation And Conservation (Assam), the Marine Aquarium Societies of North East India, and the Kaziranga Nature Conservancy of Assam.