GloFish® Tetra Care Guide - Tank Setup, Feeding & Breeding

GloFish® Tetras are brightly fluorescent varieties of the Black Skirt Tetra, created by introducing genes that produce vivid colors under normal aquarium lighting and especially striking fluorescence under blue or actinic illumination. Available color forms include shades such as red, orange, green, purple and blue, although their underlying body shape remains that of the familiar deep-bodied Black Skirt Tetra.

These are active, sociable fish with a laterally compressed body, a tall dorsal fin and a long anal fin that gives the species its characteristic skirt-like silhouette. They spend much of their time in the middle levels of the aquarium and are most confident when surrounded by members of their own kind.

The original Black Skirt Tetra inhabits slow-moving waters, flooded vegetation and forest-associated streams in South America. In these environments, submerged branches, plants and subdued light provide cover while the fish move through the open water in loose groups.

GloFish® Tetras are not a separate naturally occurring species; they are selectively sold color strains of a genetically modified Gymnocorymbus ternetzi lineage. Their fluorescent coloration does not alter their fundamentally peaceful, schooling behaviour, though individuals can become nippy or stressed when kept in unsuitable social conditions.

GloFish® Tetras are genetically modified color varieties developed from the Black Skirt Tetra, Gymnocorymbus ternetzi. The original species is native to freshwater habitats in central South America, including parts of Brazil, Bolivia, Paraguay and northeastern Argentina.

A group of GloFish® Tetras should have at least 75 litres, with a footprint around 60 × 30 cm or larger; a longer aquarium is preferable because these active swimmers use horizontal space. Use open swimming areas alongside dense plants, driftwood or other shaded retreats, with a dark, fine-grained substrate helping their colours stand out. Gentle to moderate water movement, stable filtration and a secure lid complete the setup.

Adults reach approximately 5–6 cm (2.0–2.4 in) in total length. Females are usually slightly larger and deeper-bodied than males, particularly when mature.

GloFish® Tetras are omnivorous and do best on a varied diet of quality small pellets or flakes supplemented with frozen or live foods such as brine shrimp, daphnia, bloodworm and mosquito larvae. Feed small portions that they can consume promptly, with variety helping to support good condition and colour.

GloFish® Tetras generally suit peaceful community aquariums containing similarly sized fish such as other tetras, rasboras, danios, peaceful barbs, Corydoras, kuhli loaches and smaller, calm livebearers. Avoid housing them with fin-nipping species, aggressive cichlids, territorial fish or large predators. They may nip slow-moving, long-finned fish such as bettas or fancy guppies, particularly when kept in an undersized group.

GloFish® Tetras are egg-scattering fish that can be bred in a separate, gently filtered breeding aquarium. Add a spawning mop or fine-leaved plants, condition the adults with nutritious foods, and move the adults out after spawning because they may eat the eggs. The eggs usually hatch within a day or two, with free-swimming fry requiring very small foods such as infusoria before progressing to newly hatched brine shrimp.

Females are generally plumper and have a more rounded abdomen, while males tend to be slimmer and may show a more pointed body profile. Differences can be subtle, especially in young fish; fluorescent colour is not a reliable way to determine sex.