A Detailed Explanation For “Why Do My Glofish Keep Dying?”

The charm of Glofish is an excellent addition to any aquarium. This species is also prevalent due to its ease of keeping and peaceful disposition.

Like other fish, your Glofish may die one day for some unknown reason. At that point, you might wonder, “Why do my Glofish keep dying?

Today, we will list all possible causes that can kill your Glofish. Knowing them well can help you prolong the life of your Glofish. Let’s explore right now!

Why Do My Glofish Keep Dying?

Ternetia Glofish

Your glofish can die for a variety of reasons, including:

  • Old Age
  • Disease
  • Parameters Changed So Quickly
  • Dirty Tank Water
  • Wrong Feeding
  • Wrong Tank Mates
  • The Aquarium Is Too Small
  • Don’t Cycle Your Tank
  • Stress

Old Age

No animal can escape aging, and dying of old age is inevitable. So no matter how well you take care of your Glofish, it will die one day because of old age.

Here is the average lifespan of some Glofish species:

  • Glofish Sharks: From 7 to 8 years.
  • Glofish Barbs: From 6 to 7 years.
  • Glofish Danios: From 4 to 5 years.
  • Glofish Bettas: From 3 to 5 years.
  • Glofish Tetras: From 3 to 5 years.


When your Glofish gets diseases, its immunity is compromised, making it vulnerable to many attacking pathogens. Then the situation will worsen, and your fish may end up dying.

Parameters Changed So Quickly

Sudden changes in water salinity, hardness, pH, and temperature can shock your Glofish, leading to death. That’s why you must ensure all changes and shifts in water parameters are steady and gradual.

Dirty Tank Water

Dirty water and wrong water parameters can also be the culprits that kill your Glofish. Although Glofish are tough, they will still react negatively to poor quality water and inappropriate water parameters.

We recommend setting aside time every one or two weeks to manage the aquarium. Your tasks typically include siphoning the substrate, wiping the glass, and inspecting all the equipment.

Also, it is essential to change the tank water periodically. Replacing at least 20 to 25% water weekly is wise.

You also need to ensure the aquarium water parameters are reasonable for your Glofish:

  • Water temperatures: Around 72 to 80 F.
  • pH level: From 6.0 to 7.0.
  • Water hardness: From 2 to 10 dGH.
  • Ammonia and nitrate levels: 0 PPP
  • Nitrite levels: Under 20 PPM.

Wrong Feeding

It is best to give your Glofish two meals daily with an amount they can finish within three to five minutes. Feeding your fish too much or too little can cause big problems.

Overfeeding your Glofish can lead to problems like constipation and obesity.

Besides, the leftovers will decay, making more waste than ever. Hence, it will lead to a quick spike in the levels of toxic compounds, such as nitrite and ammonia, which can kill your Glofish.

What about feeding your fish too little? It can expose your fish to malnourishment and will harm its lives. A lack of calcium in the diet can cause skull deformation and an increased mortality rate.

Wrong Tank Mates

Glofish sharks, Glofish bettas, and Glofish sharks are solitary beings who do not desire to share their space with anyone. So, worrying about them getting bored and lonely is unnecessary.

On the flip side, Glofish danios, tetras, and barbs are shoaling/schooling species that you should keep with their kind.

However, that doesn’t mean you can’t keep them with other tank mates. Just a few things to keep in mind:

  • Avoid keeping Glofish bettas with fin-nippers, such as tetras, danios, and barbs. They will constantly nip the betta’s fins, harm it, make infections, and reduce its lifespan.
  • Glofish tetras, barbs, and danios should never be kept with aggressive and big fish that can quickly gobble them up the whole.
  • You shouldn’t keep Glofish sharks with other aggressive bottom-dwellers as they will immensely stress your Glofish, which can impact Glofish’s lifespan.

Your Aquarium Is Too Small

Overcrowded tanks

Overcrowded tanks can be a severe problem for Glofish

Beginners often make the mistake of buying an aquarium and putting inappropriate fish into it without analyzing their needs and temperament. So it can lead to an overcrowded tank, and it is a death sentence for Glofish.

The minimum advised tank size for one Glofish shark is about 50 gallons. Meanwhile, for one Glofish betta, five gallons is suggested.

For other Glofish species, including barbs, tetras, and danios, you should deliver 20 to 30 gallons as these fish are schooling that should be kept in a group of at least six individuals.

Don’t Cycle Your Tank

Not cycling aquariums is also the most common mistake beginners make. But, honestly, setting up aquariums the right way is not a breeze.

In uncycled or wrongly cycled aquariums, death will occur overnight. Or, in the worst case, it will occur painstakingly slowly.



stress glofish

Stress is the cause behind the death of any fish, including Glofish. However, many aquarists overlook this factor, and the causes of stress are varied, such as:

  • Aggression
  • Loneliness
  • New environment
  • Overcrowded tank
  • Wrong water parameters.


How to Tell if Your Fish Is Dying?

Some common signs are:

  • Lethargy
  • Panting
  • Shimmies
  • Flashing
  • Loss of balance
  • Loss of appetite
  • Erratic swimming

Does Glofish Need an Air Pump?

Your Glofish will surely benefit from an air pump.

Why Did My Glofish Die Within Hours?

It could be that your fish are severely stressed during the transition from the pet shop to your house or that your tank conditions are unsuitable.

Why Did My Glofish Die in One Day?

It could be one of the reasons that we mentioned.

Why Did My Glofish Die After Changing Water?

It might have something wrong with your water parameters. Check it out immediately!


Through the above article, we have listed all possible causes that can kill your Glofish. Hopefully, they can help you solve the mystery behind your pet’s death!