Green Neon Tetra Care Guide - Aquarium Setup, Feeding & Breeding

The Green Neon Tetra is a small, streamlined characin with a vivid blue-green iridescent stripe running from the eye toward the base of the tail. A subtle red marking is usually visible on the rear portion of the body, although it is less extensive than the red stripe seen on a Cardinal Tetra. Their reflective colouring glows particularly well under subdued aquarium lighting.

These peaceful fish are active but not boisterous, spending much of their time in the middle and upper areas of the aquarium. They move together in a coordinated shoal, becoming more confident and displaying more natural behaviour when kept in a suitably sized group.

In the wild, Green Neon Tetras live in calm, tea-coloured waters created by fallen leaves, branches and other decomposing plant matter. The dense vegetation and shaded canopy help diffuse sunlight, while the water is typically very soft and naturally acidic.

Paracheirodon simulans is closely related to the Neon Tetra and Cardinal Tetra, but it remains noticeably smaller and often has a more slender appearance. Its modest adult size and peaceful temperament have made it a popular choice for planted community aquariums and carefully planned nano-style displays.

Green Neon Tetras are native to the upper Rio Negro basin in Brazil, South America, where they inhabit slow-moving forest streams, tributaries and flooded blackwater habitats. Their range is associated with clear, tannin-stained water beneath dense rainforest cover.

A group should have at least a 60-litre aquarium, ideally measuring around 60 × 30 cm or larger at the base, with open swimming space and gentle water movement. Use dark sand or fine gravel, dense plants, driftwood and shaded areas to recreate a forest-stream environment. Floating plants and subdued lighting can help the fish feel secure, while leaf litter or other natural-looking structure can complement a soft blackwater-style layout. The aquarium should be mature, stable and fitted with filtration that does not create excessively strong currents.

Up to around 2.5 cm (1 inch) in total length. Females are generally slightly deeper-bodied and may be marginally larger than males.

Offer a varied diet of high-quality micro pellets or crushed flakes supplemented with appropriately sized frozen or live foods such as baby brine shrimp, daphnia, cyclops and mosquito larvae. Their small mouths require finely sized foods, and several modest feedings are preferable to one large portion. A varied diet helps maintain their colour, energy and condition.

Green Neon Tetras are peaceful community fish and can be kept with similarly sized, gentle species such as small Corydoras, Otocinclus, pygmy rasboras, peaceful pencilfish, honey gouramis and other calm South American tetras. Avoid large or predatory fish, fin-nippers and highly boisterous tankmates, which may harass them or treat them as prey. They should also not be housed with fish whose water requirements differ substantially from soft, mildly acidic conditions.

Green Neon Tetras are egg-scattering fish that breed most readily in a separate, dimly lit spawning aquarium with very soft, acidic water and fine-leaved plants or spawning mops. Condition adults with small live or frozen foods, then introduce a pair or small group. They scatter adhesive eggs among the vegetation, after which the adults should be removed because they may eat the eggs. Hatching usually occurs within a day or two, and the tiny fry can initially be fed infusoria or other suitably small first foods before moving on to baby brine shrimp.

Females are usually fuller through the abdomen, especially when carrying eggs, while males tend to be slimmer and more streamlined. The colour pattern is otherwise similar in both sexes, so sexing young Green Neon Tetras can be difficult.