Do GloFish Need a Heater? {What Do I Need In A GloFish tank?}

Are you interested in keeping GloFish in your tank without a heater? Are there any types of GloFish that can live in an unheated tank? In this article, we will find out if GloFish need a heater.

Does Glofish Need a Heater? GloFish prefer to be kept in temperatures that do not fluctuate too much, but remain within 72-82°F. For this reason it is recommended that GloFish be kept in tanks with a heater. GloFish Danios may have the best chance at surviving in unheated aquariums.

What Temperature Should Glofish Be Kept At?

GloFish are popular and great for beginners in the fish keeping hobby. Depending on their species, GloFish can grow anywhere from 1.5 to 6 inches.

Please keep the temperature constant in the range of 72 to 82 degrees Fahrenheit.

GloFish are genetically modified and continue to come out in varieties of colors and species. Some of which are listed below:

  • Zebra danios 
  • Black skirt tetras
  • Tiger barbs 
  • Rainbow shark
  • Betta fish

GloFish are marketed and manufactured under trademarked colors such as Starfire Red®, Electric Green®, Sunburst Orange®, Cosmic Blue®, Galactic Purple®, and Moonrise Pink®.

What Do Glofish Need in Their Tank?

With the exception of hardy GloFish Danios, the rest of the types of GloFish would require a heater in their tank to maintain temperatures between 72 to 82°F.

GloFish are playful and active in a group of 5 or more. Adding decorations and planted areas give them spaces to play and explore throughout the day while resting comfortably at night when you shut off the tank lights.

The following items should be included in a GloFish tank:

  • Filter
  • Heater
  • Decorations
  • Gravel substrate
  • Blue LED aquarium lighting

Only the filter and heater are absolutely necessary for their survival but the extra suggested additions above create the best environment for your GloFish to thrive actively with their eye-popping colors.

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How To Set Up A Heater For Glofish

Please consider the heater placement and heater size when setting up the appropriate option for your tank and Glofish needs. They cannot survive without stress in cool waters. Disease, stunted growth and a shorter lifespan will result.

Heater Placement

You will have to choose the best type of heater for the tank that you own. Placing the heater near the filter allows for the circulation of water to be warmer. The lower the submersible heater is, the better it can warm up the entire tank.

Heater Size

The right size heater for your tank depends on the amount of wattage. The general rule of thumb is a heater with 5 watts per gallon of water in a tank that is less than 55 gallons in total size.


  1. Before adding in your GloFish, make sure the temperature has reached a suitable range between 72 to 82 degrees Fahrenheit.
  2. If your heater does not come with a thermometer, please check manually to make sure the temperature continues to stay within this range.

Heater Varieties For Glofish

There are various options of heaters available for your GloFish tank including:

  • Hanging Heater
  • Submersible Heater
  • Circulation Heater
  • Flange Heater 
  • Flat Heater

For all types of heaters, try to keep the water level above the heating mechanism itself. Submersible heaters are excellent for larger tanks, but GloFish will be fine in 15 to 20 gallon tanks with a hanging heater that is inexpensive.

Pros And Cons Of Heater For Glofish

Choosing the cheapest available heater on the market comes with its own set of risks. Choosing to not use a heater may end up resulting in stressed, stunted, sick or dying GloFish.

Here are some pros and cons for getting a heater to keep your GloFish comfortable:


  • They provide warm, comfortable water conditions .
  • Heaters are fairly inexpensive.
  • They prevent temperature fluctuations.


  • Cheap heaters with exposed heating tubes could burn your GloFish.
  • Decorations and plants could also get burned.
  • Electric bills will be higher.

We highly recommend buying a new heater that is suitable for a 20 gallon tank to keep 5-6 GloFish warm and healthy in your aquarium.

Can Glofish Live in Regular Light?

GloFish also follow a diurnal cycle. It’s best to turn off all aquarium lights including the blue LED lights that are recommended for GloFish during the day to give them the eye popping colors that we are pleased to look at.

Stick to a 12-hour schedule where half of the day is lit and the other half is completely shut off to allow your goldfish the opportunity to rest.

How Many Glofish Can I Put in a 10 Gallon Tank?

GloFish sizes range between 1.5 to 5 inches in length depending on the species. You might be able to keep 5-6 GloFish tetras in a 10 gallon tank.

It is highly recommended that you surpass this minimum requirement because all GloFish varieties exhibit active and playful swimming behavioral traits.

We do not recommend a 10 gallon tank for 5-6 GloFish and we also don’t recommend keeping less than that number.

GloFish are comfortable schooling in groups with at least five of them together. A 15 to 20 gallon tank would work much better.


If you want to take on the experiment of keeping GloFish in a tank without a heater, we recommend using only Zebra Danio species of GloFish. They are hardier and seem to have an ability to withstand larger temperature fluctuations.

Overall, if you do not wish to stunt their growth or expose them to diseases and possibly reduce their lifespans, it’s best to get a heater that isn’t too expensive.

Make sure the heater is new and trustworthy to either submerse or hang on the back of a tank intended for a 15 to 20 gallon tank for 5-6 GloFish.


Thank you for visiting for all your aquarium needs. We have plenty more articles on GloFish and other Aquatic Life that may interest you. Goodbye for now!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.

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