Do Guppies Really Need A Heater In Their Tank?

While guppies can thrive in a range of temperatures, most aquarists should use a heater to maintain a stable tank environment.

When setting up my own dedicated guppy tank, I wanted to find the most economical way to heat it, especially with the current high energy prices.

This prompted me to research various options for heating a guppy tank and question whether guppies even need a heater and I wanted to share my findings with my readers.

What Is The Purpose Of A Heater In A Guppy Tank?

Guppies Near The Heater In Their Tank
Guppies Near The Heater In Their Tank

The primary purpose of a heater in a guppy tank is to maintain a stable, consistent temperature that meets the needs of the guppies.

Many people believe that an aquarium heater will constantly run, leading to high electricity costs, but this is a misconception. Once your guppy tank reaches the desired temperature, the heater will only activate for a few minutes each hour, keeping energy costs lower than expected.

Your home’s central heating system can affect your guppy tank’s water temperature. In some homes, the room’s ambient temperature might be sufficient to warm the tank, potentially offering a more budget-friendly heating option since gas is often cheaper than electricity.

Despite being tropical fish, guppies can tolerate a surprisingly wide range of temperatures, with 63-82°F (17-28°C) being commonly recommended. Many central heating systems can maintain this temperature range without the need for an additional heater.

Here are some common indicators to watch for with your guppies:

Too Hot

  • Rapid Or Laboured Breathing.
  • Increased Restlessness.
  • Higher Levels Of Aggression.

Too Cold

  • Lethargy Or Reduced Activity.
  • Reduced Appetite.
  • Paler Coloration.

Do Guppies Need A Heater?

My Guppy Tank
My Guppy Tank

In warmer regions, guppies may not require a heater in their tank, but most people should consider adding one to their aquarium.

Even though I mainly depend on my central heating system to warm my guppy tank, I still have a Fluval T50 heater as a backup in case the water temperature drops too low.

The built-in sensor in the heater detects any potential issues with the water temperature and activates the heater if necessary.

This setup gives me peace of mind, knowing that my guppies will be safe and their water temperature will be properly maintained.

Pros And Cons of Adding A Heater To Your Guppy Tank!


  • Consistent Temperature
  • Promotes Activity
  • Supports Breeding
  • Expands Habitat Options
  • Safety Features


  • Additional Costs
  • Risk of Malfunction
  • Potential Hazard
  • Aesthetic Concerns
  • Space Consumption

Here is a breakdown of the pros and cons of using a heater in your guppy tank to help you decide if you should use a heater or not.


Consistent Temperature: Heaters help maintain a stable temperature within the tank, ensuring that the water doesn’t become too cold or experience rapid fluctuations to help keep your guppies happy.

Promotes Healthy Growth and Activity: A consistent, suitable temperature can promote the health and activity level of guppies and reduce the risk of diseases that come with temperature stress.

Supports Breeding: If you’re interested in breeding guppies, a consistent temperature is crucial for optimal breeding conditions and the survival of fry.

Expands Habitat Options: If your room or house temperatures vary a lot, especially during different times of the year, a heater can expand the range of rooms in which you can keep a guppy tank.

Safety Features: Modern heaters often come with features like auto shut-off when the water level is low, or if the heater is removed from water, reducing the risk of damage or accidents.

My Guppy Tank Heater
My Guppy Tank Heater


Additional Costs: Purchasing a good-quality heater can be an added expense. Additionally, there’s a continuous small, electricity cost.

Risk of Malfunction: Like any electronic device, there’s a small risk of malfunction. A heater that fails to turn off can cook the tank, while one that fails to turn on can leave the tank too cold.

Potential Hazard: If handled incorrectly, a heater can be a hazard. There’s a risk of it breaking if dropped or knocked and some cheap heaters can be prone to shorting out.

Aesthetic Concerns: Some aquarium enthusiasts feel that heaters and their cables can detract from the natural look of an aquarium setup.

Space Consumption: In smaller tanks, a heater can consume valuable space and might require careful placement to avoid interfering with plants, decorations, or fish movement.

Alternatives To Heaters In Guppy Tanks!

The Heater In My Betta Tank
The Heater In My Betta Tank

The main alternatives to using a heater in your guppy tank are:

  • Room Heating
  • Insulation
  • Positioning
  • Sunlight

Here is a short breakdown of each of these options but a decent heater is usually the best option.

Room Heating: You can maintain a suitable room temperature for the room that houses your guppy tank. This is the most common alternative to using a heater in a guppy tank, especially if you keep a “fish room” with many tropical aquariums that all require heating.

Insulation: Insulating the aquarium with reflective foam is a surprisingly easy way to retain heat. Applying foam to the base and rear of your aquarium may be enough to maintain a steady water temperature in warmer locations.

Positioning: Place the tank in a warm part of the house, preferably away from drafts, windows, or external walls which tend to be cooler. Most people initially think of their radiators but the kitchen in my house maintains a temperature suitable for guppies year round.

Sunlight: Using natural sunlight can help warm the tank. However, this method requires careful monitoring as direct sunlight can lead to rapid overheating and can also encourage excessive algae growth.

Heated mats can end up costing far more than a regular aquarium heater so they should be avoided if possible even though some people recommend them on social media.

Final Thoughts

While guppies can tolerate a broad range of temperatures, a consistent environment is crucial for their well-being, especially given that many modern guppies are more delicate than their wild counterparts.

For many aquarists, an aquarium heater offers peace of mind, ensuring a stable temperature and reducing the risks associated with rapid temperature fluctuations.

However, it’s essential to weigh the pros and cons, and consider alternative heating methods, to determine the best approach for each individual setup.