Do Glofish Need a Heater?

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Let’s start this topic by answering the question in the title unequivocally. Yes, Glofish need a heater, because all glofish species are tropical fish, which thrive in colder water temperatures.

I would even go so far as to say that all fish species require a heating system, no matter the species they belong to.

Many people rely on room temperature to stabilize the temperature of the tank water, but that’s a poor system, in my opinion.

You have no way of monitoring and adjusting the water temperature without a reliable heating system, which can hurt temperature-sensitive species.

Rapid or frequent temperature fluctuations can hurt even the most adaptable fish species, let alone the more sensitive ones.

When it comes to Glofish, this is a group of 5 (so far) species with different needs and temperature preferences. Let’s check each species’ ideal temperature ranges to see where they stand.

Best Temperature for Glofish

There are 5 species of Glofish available at the moment, with more planned to be engineered over time.

These are:

Barb Glofish

Ideal Temperature – 75-80 °F

The interesting aspect about tiger barbs is that they are one of the most adaptable fish species you can get.

They prefer an overall temperature around 75-80 °F, but they will do just fine at temperatures outside these ranges.

This makes tiger barbs compatible with a variety of fish species that don’t necessarily share the same temperature goldilocks zone.

That being said, they do hate rapid temperature shifts, which makes tank heaters a worthy and necessary investment.

Keep the temperature somewhere close to 80F, as warmer waters will keep the barbs more active and comfortable in the long run.

You can adjust the temperature at any point if you think your barbs are not comfortable in their current setting.

Tetra Glofish

Ideal Temperature – 72-76 °F

Neon tetras are a curious case since these are tropical fish but don’t share the temperature needs of other tropical species.

Guppies, for instance, are also a tropical species and prefer temperatures between 72 and 82 °F. Tetras can’t go that high, as waters warmer than 76 will make them uncomfortable.

With that said, tetras are more comfortable at temperatures around 72 to 74 °F but require higher temperatures during the breeding phase.

At this point, you need to increase the temperature near their upper limit to promote the breeding behavior.

All this goes to show that tetras absolutely need a heater. You can’t adjust their environmental temperature with the necessary precision if you don’t have a reliable heating system.

It’s also worth noting that tetras aren’t really fond of sudden or frequent temperature fluctuations.

Betta Glofish

Ideal Temperature – 72-81 °F

Bettas are very adaptable fish but also very sensitive to sudden temperature fluctuations.

They also require more or less pristine water conditions to avoid health issues along the way.

It’s also important to note that bettas prefer water temperatures in the mid-70s with as little fluctuations as possible.

This demands the presence of a water heater to monitor and adjust the temperature to the ideal parameters.

Danio Glofish

Ideal Temperature – 70-78 °F

Zebra danios are highly adaptable and hardy fish, capable of withstanding significant temperature fluctuations in their environment.

This adaptability is what makes the danios great for novice fish keepers and ideal for community tanks.

Stable and warm waters will make the danios more active within their habitat and boost their reproductive rates.

The fact that zebra danios can withstand temperature fluctuations with relative ease qualifies them as fit tank mates for many fish species.

Even so, a water heater is necessary to provide danios with a stable and comfortable habitat.

Shark Glofish

Ideal Temperature – 75-81 °F

Rainbow sharks are the most sensitive species on this list. They prefer warmer waters than other species and are extremely sensitive to temperature fluctuations. Water quality also needs to be as close to pristine as possible. Otherwise, they will experience health problems and become vulnerable to diseases, parasites, or bacterial infections.

A reliable heater is a vital addition to your Glofish shark tank, without which you cannot provide the fish with an adequate and safe environment. As a side note, rainbow sharks aren’t really meant for community tanks due to their territorial behavior and a rather violent personality.

Plus, they can’t really accommodate to other species’ environmental requirements, which is why I recommend keeping rainbow sharks in single-species tanks. And, whatever you do, do not keep more than 1 male in the same tank. Male sharks are particularly aggressive towards one another.

Heater Type and Size for Glofish

The heating system’s type and size should consider for your Glofish tank vary depending on a variety of factors.

These include the tank’s size, the Glofish species, room’s temperature, whether the tank is single species or community-based, etc.

As a general idea, there are 4 types of heaters to consider for your aquarium based on their positioning:

  1. Immersible
  2. Submersible
  3. Substrate heaters
  4. Filter heaters

There are 2 additional categories, dividing filters by system setup.

These can be:

  1. Canister filters – More effective at cleaning, but also more demanding in terms of maintenance and more expensive. It’s great for aquariums with small fish since they don’t risk getting sucked in. They are also perfect for larger community tanks due to the increase in power output.
  2. Power filters – Unlike what their name suggests, power filters are less powerful than canister filters. The several plusses I would like to mention are affordability and that they are easier to clean and maintain. On the downside, they are not fit for small fish since they can get sucked in.

Ultimately, you should choose the type of filtering system that best fits your aquarium needs. Consider how large the tank is and what types of Glofish species you’re looking to house.

Not all of them display the same environmental requirements, and strong water currents may prove harmful to many of them.

With that said, having a reliable filter is a must for any tank, no matter the fish species.

Can Glofish Survive in Low Temperature?

The answer depends on how low the temperature is. Most Glofish will survive for some time in waters colder than they’re used to, but you shouldn’t test their limit.

Excessively cold waters, beyond what their comfort zone demands, can put them at risk of temperature shock. This is a deadly condition that might rush your fish into coma and death within several hours to minutes in extreme cases.

But the situation doesn’t even need to go there. Your fish can also experience weaker immune systems due to living in cold water, which will render them vulnerable to health problems.

They will also appear more lethargic, display difficulties breeding, and have difficulties eating and swimming.

These issues make for probably the best marketing tactic for aquarium heaters. Get one and keep your Glofish safe and healthy.


Glofish don’t differ much in temperature requirements from their non-glowing counterparts.

Or in terms of pretty much any other environmental preference or behavioral tendencies.

I suggest getting a reliable heater even if you think your fish needs one. Simply because a heater will allow you to provide your fish with optimal temperatures and minimize the risk of fluctuations.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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