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Like all fishes kept in an aquarium, GloFish (also known as fluorescent fish) can die from a variety of causes. Even so, some of the reasons they die are more common than others.
By considering several factors in this help guide, especially their diet and environment, the information should help you identify some reasons why GloFish die prematurely.
As the name suggests, fluorescent fish glow in bright and vivid colours (under certain lighting conditions).
Genetic modifications in some fish families means they shine brighter than others - especially under blue or ultraviolet (UV) light.
The original development aimed to help scientists detect environmental pollutants.
Nowadays, due to their unique appearance, they have become popular as ornamental fish in home aquariums.
The fluorescence is due to the incorporation of genes from fluorescent marine organisms, including coral or jellyfish, into the genome of the fish. The most common types of freshwater fish that have been developed as GloFish, include:
By and large, you won't find GloFish living in the wild because they are mostly bred in captivity. Moreover, they're not released into natural ecosystems in case they disrupt the local biodiversity.
Note: Even though they were the first genetically modified animals to be sold as pets, some countries regulate the sale and distribution of GloFish - including the United Kingdom.
In general, caring for GloFish is much the same as looking after their non-fluorescent counterparts. So, they have certain requirements relating to an appropriate tank size, water conditions, and having a healthy diet.
If you are new to fishkeeping as a hobby, you need to understand that GloFish will require enough space to swim around and explore different sections of the aquarium.
For example:
Even though they are easy to care for, if you're keeping a shimmering shoal of GloFish Danios you'll need to have a 10-gallon tank as a minimum. Likewise, larger species will require even more space.
In other words, if your GloFish are dying inside the tank you should check the tank size is suitable for the species - as well as the number of GloFishes you have.
Excessive fish waste, uneaten food, and decaying plants release toxins into the water. Often, this is the main cause of high levels of ammonia, nitrite, or nitrate.
The best way to check the water quality is to use a test kit. Furthermore, perform partial water changes (10-25% every week) and make sure the water is properly cycled before adding any fish.
Remember, chlorine found in some tap water is toxic for fishes. Hence, you can use a water conditioner to remove excessive amounts of chlorine and chloramine.
For the most part, fluorescent fish prefer a pH between 6.5 and 7.5. Test the water and adjust it as needed using aquarium-safe products.
Pro Tip: Another segment explains the aquarium nitrogen cycle and why it's so important for anyone who keeps GloFish in a fish tank.
Overcrowding in fish tanks can lead to stress, poor water quality, and aggression. To solve this problem, follow the general rule of one (1) inch of fish per gallon of water - and adjust the ratio for different fish shapes and activities.
Plus, having inappropriate tank mates is going to create unwanted problems for keepers of GloFishes. Aggressive tank mates, or fish with incompatible water requirements, can harm or stress compatible or peaceful species.
Other causes of stress include:
Make sure you provide enough plants or decorations to create hiding places, avoid tapping on the glass, and limit the number of sudden light changes.
GloFish are a tropical species. As such, they are going to need a stable water temperature between 22-28° Celsius (72–82° Fahrenheit).
This is an easy fix if you're using an aquarium heater and thermometer to maintain a stable water temperature.
Feeding too much - or providing unsuitable food - is likely to harm your fish. Instead, feed them small amounts - and no more than two (2) times each day.
Use high-quality tropical fish flakes or pellets, supplemented with occasional treats, such as freeze-dried or frozen bloodworms.
Symptoms such as unusual swimming, staying at the bottom of the tank motionless, white spots, belly bloating, or lethargy could indicate illness.
The solution?
Quarantine new fish before you add them to the tank and research any obvious symptoms to identify common fish diseases. Using appropriate treatments will help.
When you introduce new fish, the sudden change in water chemistry or temperature can be too much of a shock and kill them.
So, remember to acclimate new specimens by floating the bag in the tank for at least fifteen (15) minutes. Then, gradually mix some tank water into the bag before you let them swim out of the bag and into the aquarium.
Some GloFish species, especially those bred in poor conditions, may already have some genetic weakness. Plus, many will die a natural death when they are nearing the end of their normal lifespan (e.g. two to five years).
Nonetheless, it's very important for beginner aquarists to buy their fish stock from reputable sources and keep a track of their age.
If you have GloFish and they start dying without warning, it's worth reviewing all these factors above. Testing the water parameters and monitoring fish behaviour can also provide invaluable clues about the underlying problem.
Pro Tip: The main section contains tips and advice for troubleshooting issues with fish kept in an aquarium or an outdoor pond.