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GloFish Tetra

Gymnocorymbus ternetzi

Also called Electric Green Tetra, Starfire Red Tetra, Sunburst Orange Tetra, Cosmic Blue Tetra, Galactic Purple Tetra

VarietyShort profile

From Developed in the United States by Yorktown Technologies (now GloFish LLC, owned by Spectrum Brands) from the Black Skirt Tetra, which is native to the Paraguay and Guaporé River basins in Brazil, Bolivia and Argentina.12

At a glance the quick version

Length3.8 to 6.4 cm314
Lifespan3 to 5 years14
Sizetiny

Adult size 1.5 to 2.5 inches (3.8 to 6.4 cm).

Vibrant fluorescent colours that glow under blue light
Easy to care for and suitable for beginners
Peaceful schooling behaviour when kept in groups
Hardy and adaptable to a range of water conditions
314

Looks how to spot one

scales

The GloFish Tetra has the same tall, diamond-shaped body as the Black Skirt Tetra, but its muscle tissue expresses fluorescent proteins that glow brightly under blue or ultraviolet light. The colour is inherited and does not fade.31

ColoursElectric GreenStarfire RedSunburst OrangeCosmic BlueGalactic PurpleMoonrise Pink3

Personality what they are like

Generally peaceful and lively when kept in a school of at least 6 to 12 fish. They can show fin-nipping behaviour towards slower or long-finned tank mates, but this is usually reduced when they are in a proper group.12

Daily activity how busy a day looks

Active swimmers that need plenty of open swimming space. Provide a tank at least 20 gallons (75 litres) for a small school, with some planted areas and floating vegetation to create shaded spots.12

Grooming and care the hands-on bits

Standard aquarium maintenance: regular partial water changes, a good filter, and stable water parameters. No special grooming needed.1

Home where they are happiest

Tropical freshwater aquarium with temperature 20-26°C (68-79°F), pH 6.0-8.0, and soft to moderately hard water. A minimum tank size of 20 gallons (75 litres) is recommended for a small school. Provide open swimming areas and some hiding places among plants or decor.125

Food basics what goes in the bowl

Omnivorous. Feed a high-quality tropical flake or micro-pellet as a staple, and supplement two or three times a week with frozen or live foods such as brine shrimp, daphnia or bloodworms.12

Company who they like around

A schooling fish that must be kept in groups of at least 6, ideally 12 or more, to feel secure and reduce fin-nipping. Compatible with other peaceful community fish such as danios, rasboras, other tetras, livebearers and peaceful bottom dwellers like Corydoras. Avoid slow-moving or long-finned tank mates.12

The story where it all began

The GloFish Tetra is a genetically modified variety of the Black Skirt Tetra (Gymnocorymbus ternetzi). It was created by inserting a fluorescent protein gene from a jellyfish (Aequorea victoria) or sea anemone into the fish's embryos, so that the fish glows brightly under blue or ultraviolet light. The first GloFish were developed in the early 2000s by Yorktown Technologies (later GloFish LLC, owned by Spectrum Brands) and were originally intended for use in detecting environmental pollutants. The GloFish Tetra line was launched around 2013. Unlike dyed fish, the colour is inherited and stable. After studies confirmed that these fish cannot survive in the wild, they were approved for sale in California in 2015. The GloFish Tetra differs from the plain Black Skirt Tetra only in its fluorescent colouration; its care, size, lifespan and temperament are identical.3167

Recognised by the official bits

California Department of Fish and Wildlife
Approved for sale in California in 2015 after studies showed GloFish Tetras cannot survive in the wild.6

The care rhythm a typical week and year

A typical home-care rhythm for a GloFish Tetra. A starting point, not a vet's advice.

Owner questions the things everyone asks

How often should I feed my GloFish Tetra?

Feed your GloFish Tetra small amounts once or twice daily. Furry Diary's starting plan suggests feeding every day with small portions. Supplement with frozen or live foods two to three times a week for variety. Always follow the food label and consult your vet for exact amounts.12 Pet Wiki plan

What does a GloFish Tetra eat, and what should it never eat?

They are omnivores and thrive on a high-quality tropical flake or micro-pellet as a staple. Offer frozen or live foods like brine shrimp or bloodworms a few times a week. Avoid feeding anything not designed for tropical fish, such as human foods, and never overfeed. For a complete list of foods to avoid, ask your exotic-pet vet.12

How much space does a GloFish Tetra need?

A minimum tank size of 20 gallons (75 litres) is recommended for a small school. They are active swimmers and need plenty of open swimming space, along with some planted areas and floating vegetation for shade. A larger tank is even better for a bigger group.12

What temperature, light or water does a GloFish Tetra need?

They need a tropical freshwater aquarium with a temperature between 20-26°C (68-79°F) and a pH of 6.0-8.0. Soft to moderately hard water is ideal. Light requirements vary, so it's best to ask a good breeder or exotic-pet vet for specific lighting advice.125

How often should I clean a GloFish Tetra's home?

Perform a partial water change of about 25% every week, and clean the glass at the same time. Rinse the filter monthly in old tank water (never tap water) to keep it working well. Also test the water weekly to ensure stable conditions.1 Pet Wiki plan

Can a GloFish Tetra live with others?

Yes, they are peaceful schooling fish that must be kept in groups of at least 6, ideally 12 or more. They get along well with other peaceful community fish like danios, rasboras, and Corydoras. Avoid slow-moving or long-finned tank mates to prevent fin-nipping.12

How long does a GloFish Tetra live?

With proper care, your GloFish Tetra can live for 3 to 5 years. Providing a stable, clean environment and a balanced diet will help them reach their full lifespan.14

Can I handle a GloFish Tetra?

It's best not to handle them; they are delicate aquarium fish and handling can cause stress or injury. If you need to move them, use a soft net gently. For any handling concerns, consult your exotic-pet vet.

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

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Where this comes from

Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.

  1. fishstores.org: glofish tetra fishstores.orgused for origin, length cm, lifespan years, coat or body, best traits, temperament, activity needs, grooming or care, habitat needs, diet basics, social needs, history
  2. seriouslyfish.com: gymnocorymbus ternetzi seriouslyfish.comused for origin, temperament, activity needs, habitat needs, diet basics, social needs
  3. liveaquaria.com: 3598 liveaquaria.comused for length cm, coat or body, colours, best traits, history, fun fact
  4. petzonesd.com: blogglofish tetra d3a67f petzonesd.comused for length cm, lifespan years, best traits
  5. fishbase.org.au: 4682 fishbase.org.auused for habitat needs
  6. petzonesd.com: sunday species spotlight black skirt tetraglofish gymnocorymbus ternet petzonesd.comused for history
  7. waves-vagues.dfo-mpo.gc.ca: 4095626x waves-vagues.dfo-mpo.gc.caused for history
  8. urbanfishkeeping.com: glofish tetra urbanfishkeeping.com

Checked 2026-11-03. Text is written in our own words from these sources.