GloFish Danio

Looks how to spot one

Fusiform (torpedo/streamlined) body shape

GloFish Danios have the same sleek, torpedo-shaped body as ordinary zebra danios, but they glow in vivid fluorescent colours due to a added gene from jellyfish or sea coral. Their fins are clear and they have a constant, darting swimming style.31

Personality what they are like

GloFish Danios are peaceful, lively fish that constantly dart around the top and middle of the tank. They are shoaling by nature and feel safest in groups of five or more. They may chase each other but rarely cause injury, though they can nip the fins of slow-moving, long-finned tank mates.23

Daily activity how busy a day looks

High. They are hyperactive swimmers that need plenty of open swimming space and a moderate current from a filter or powerhead. A long, planted tank is ideal.2

Grooming and care the hands-on bits

Very low maintenance. Perform weekly water quality checks and change 10 to 25% of the water every 2 to 4 weeks. Provide a hood to prevent jumping. Turn off lights at night to give them a rest period.62

Home where they are happiest

Minimum tank size 10 to 11 gallons. Water temperature 72 to 82°F (22 to 28°C), pH 6.0 to 8.0, hardness 5 to 20 dGH. Provide plenty of substrate, rocks, hiding places, and plants. They are not venomous, protected, or illegal to keep in most countries, but check local regulations as they are genetically modified.356

Food basics what goes in the bowl

Omnivore. Feed a varied diet of high-quality flakes, pellets, frozen or freeze-dried foods such as bloodworms and brine shrimp. Include foods rich in carotenoids to help maintain their bright colours. Feed small amounts twice a day, only what they can eat in 1 to 2 minutes.36

Company who they like around

Shoaling fish that must be kept in groups of at least five. They are peaceful and can live with other non-aggressive, similarly active fish. Avoid slow-moving, long-finned species as GloFish may nip their fins.42

The story where it all began

GloFish Danios are a genetically modified variety of the common zebra danio (Danio rerio). They were first created in 1999 by Dr. Zhiyuan Gong and his team at the National University of Singapore, who inserted a green fluorescent protein gene from a jellyfish into a zebrafish embryo. Later, red and orange varieties were made using genes from sea coral. The fish were originally intended to detect water pollutants, but were soon commercialised as pets. In 2003, Taiwan became the first country to approve their sale, and later that year they entered the US market after the FDA determined they posed no environmental risk. The GloFish brand is now owned by Spectrum Brands. Unlike dyed fish, their colour is inherited naturally and does not fade.1

Recognised by the official bits

U.S. Food and Drug Administration (FDA)

Determined in December 2003 that GloFish pose no environmental risk, allowing sale in the United States.1