What Are GloFish?

Sean Perry, DVM
By Sean Perry, DVM on Aug. 26, 2022
Glofish in tank

GloFish® are an exciting new type of fish that are are becoming more popular because of their vibrant colors, making them attractive display animals for any freshwater fish tank.

GloFish get their name from their fluorescent coloration. They come in a variety of fluorescent colors such as red, pink, orange, green, blue, and purple. These colors a called Starfire Red, Electric Green, Sunburst Orange, Cosmic Blue, Galactic Purple, and Moonrise Pink. GloFish actually come from a number of different fish species. All these colors can be found in the following species of fish:

  • Zebra fish (Danio rerio)

  • Tetra (Gymnocorymbus ternetzi)

  • Tiger barbs (Puntius tetrazona)

  • Rainbow shark (Epalzeorhynchos frenatum)

  • Betta (Betta trifasciata)

Where Do GloFish Come From?

GloFish are one of the first genetically modified animals to become popular within the pet trade. These fish were developed by introducing different fluorescent proteins into the genome of the fish at the early stages of development. The goal of producing fish that had these fluorescent proteins was to improve biomedical and environmental research. It was thought they would be able to detect pollution within the environment. Now these fish are bred specifically for the ornamental fish pet trade.

The genes that are responsible for the color of GloFish have been placed within the genetic code of each fish, so they are passed on from generation to generation. These genes produce proteins that fluoresce which give GloFish their “Glo!” GloFish absorb light in a specific wavelength then re-emit light, giving them their glowing appearance. Their color can be enhanced by blue LED, actinic, and black lights.

GloFish are not available in all places due to legal issues surrounding their genetically modified state. Be sure to determine if GloFish are legal in your state before your search.  

GloFish Communities

GloFish can live anywhere between 3-8 years under the appropriate husbandry conditions. As with all fish, selecting fish species to live with your GloFish is important to maintain harmony within your fish tank. Community species of GloFish fish can be safely housed together with other community fish species. GloFish sharks and GloFish bettas should be housed individually due to their aggressive nature.

GloFish are more vulnerable to predation compared to the wild forms of each species. This is important to know when selecting additional fish for a fish tank. Do not include any aggressive fish species within your tank as they might try to prey upon the GloFish. 

GloFish Tanks

Habitat size should be based on the adult size of the species you are keeping and the amount of fish you are keeping within the aquarium. GloFish can be successfully housed in tanks from 5 gallons for the small Zebra fish to aquariums greater than 20 gallons for multiple GloFish species.

Water Quality for GloFish

As with any other fish species, water quality is extremely important in maintaining a thriving fish tank. It’s important to use conditioned water for your fish tank. This neutralizes any impurities or chlorine in the water that can be harmful to the fish. Proper filtration is also necessary to maintain optimal water quality to ensure health. Water circulation should be provided for water currents and ensure high oxygen levels in the water, as GloFish are found in habitats with high water oxygen levels.

Regularly test the water quality of your tank. Stable values of pH, ammonia, nitrate, nitrite, and water temperature are vital to the health of any aquatic habitat. Home water quality test kits can be purchased online. Water quality should be maintained in the standard ranges for freshwater tanks.

An aquarium heater is also important to ensure stable water temperatures. An appropriate water temperature for most GloFish species is 72-82 degrees F.

Tank Enrichment for GloFish

GloFish can benefit from having enrichment within their habitats. Décor can be used to provide structure and hides within the environment. Structures that provide shelter include plants, rock caves, and hollow logs. Additional environmental décor, marketed under the GloFish brand, can add fluorescent color to the rest of the habitat including items such as substrates and plants.

What to Feed a GloFish

GloFish can be fed a balanced diet of flakes, pellets, and frozen or freeze-dried food items. Diets that are high in carotenoids and beta carotene may help increase the coloration of your GloFish. Offer small amounts of food to your fish once or twice a day. Only offer enough food for your fish to consume all food items within 1-2 minutes of feeding. For any frozen food items, immediately thaw them prior to feeding.

GloFish can make fantastic pets for adults and kids alike. If you are looking to have a pet fish with vibrant colors, GloFish are a great option for a new freshwater tank. With many Glofish species options available, these beautiful fish can be housed in many tank sizes in a variety of different homes. These fish can provide hours of entertainment for your entire family.

Featured Image: iStock.com/z1b

Sean Perry, DVM


Sean Perry, DVM


Dr. Sean Perry completed his undergraduate degree at the University of California, Santa Cruz, earning a Bachelor of Science in...

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