Green neon tetra (Paracheirodon simulans) care guide

Group
Freshwater fish
Other names
False neon tetra, Blue neon tetra
Family
Acestrorhamphidae (American tetras; formerly Characidae)
Origin
Middle and upper Rio Negro in Brazil and the upper Orinoco system on the Venezuela–Colombia border; found only in blackwater streams.
Water
freshwater
Maximum size
2.5 cm
Temperature
23–28°C
pH
4–6.5
Hardness
Very soft to soft, 1–8 dGH
Minimum tank
41 litres
Care level
intermediate
Temperament
peaceful

Care

The smallest of the neon-type tetras and a natural shoaling fish, so keep at least 8–10, and ideally more. A tank with a base of 45 × 30 cm (around 41 litres) is enough for a small group. This is a true blackwater species, found only in acidic, tea-stained water. A heavily planted, natural-style tank with a sandy substrate, driftwood, dried leaf litter and dim lighting suits it best. Aim for warm, very soft, acidic water: around 23–28 °C and a pH well below neutral, with hardness kept low. Green neons are sensitive to changes in water chemistry and should only go into a fully mature, stable aquarium. They are not bred commercially, so all stock is wild-caught; they are less common and dearer than neons and cardinals and may need careful acclimatisation and quarantine. You can tell them from neons and cardinals by the greener stripe running right to the tail and the much duller red on the lower body. Exported far less often than neons or cardinals (about 17,000 fish in 2002); collection for the aquarium trade is its only known threat and is not considered significant. Sources: Seriously Fish (seriouslyfish.com/species/paracheirodon-simulans/); FishBase (fishbase.se/summary/Paracheirodon-simulans.html); Wikipedia (en.wikipedia.org/wiki/Greenneontetra). Checked October 2026.

Diet

An omnivore and micropredator. Offer a good-quality very small flake or micro-granule alongside regular small live or frozen foods such as chironomid (bloodworm) larvae, mosquito larvae and Daphnia; small foods suit its tiny mouth.

Breeding

Rarely bred in aquariums and not produced commercially, so there is little reliable information. It is an egg-scatterer like its relatives, and the same approach used for neon and cardinal tetras – a separate, dark tank with very soft, acidic water, fine-leaved plants or mops, and removal of the adults after spawning – is the obvious starting point. Mature females are rounder-bodied and slightly larger than males.

Compatibility and tank mates

Peaceful but timid, and best with other small, quiet fish that like soft, acidic water: small tetras, pencilfish, hatchetfish, small Corydoras and other small catfish. Too small for most community tanks with medium-sized or boisterous fish, and avoid anything that could eat it.

Last updated 4 October 2026. Community-edited care guide on Aquatic-Auctions.

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