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Green Neon Tetra

Scientific Name: Paracheirodon simulans
Family: Characidae, Hemigrammus Clade

About the Green Neon Tetra

Species Type: Freshwater Fish
Category: Characins

Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.

Origin: Middle Rio Negro basin; found by Heiko Bleher as far north as the Vichada in Columbia.

Compatibility/Temperament: Very peaceful and quiet, suitable for an aquarium of similar soft and acidic water fish. Must be kept in a group, minimum six but preferably more. The fish generally remain together in a shoal.


Similar in appearance to but smaller than the Cardinal Tetra; the red below the "neon" lateral line is less brilliant. The neon line extends from the eye to the caudal peduncle (base of the caudal fin) and is thus the longest and straightest of the four "neon" species. This gives this fish a more slender, straight appearance.

To date, all fish commercially available are captured in the wild. This species shares identical habitat and water parameter requirements with the Cardinal Tetra, and the two species are sympatric over portions of their range. The species was discovered in 1962 from individuals that were mixed in with cardinal tetras. The pH of the habitat waters ranges from 3.4 to 4.8, with hardness so low it can hardly be measured. Neither fish fares well in tanks with hard and basic (alkaline) water. To replicate their habitat, the aquarium should have a sand or fine gravel substrate, and plenty of aquatic plants like Echinodorus (swords), Cabomba, Pennywort, and floating plants. Water flow from the filter should be minimal, with subdued lighting. This species prefers the middle regions in the aquarium, unlike its cousin the Cardinal Tetra which prefers the lower regions.

The iridescent blue/green line contains pigment cells known as iridophores (or sometimes guanophores); these reflect light using plates of crystalline chemochromes made from guanine. In light, these generate iridescent colours due to the diffraction of light within the stacked plates.

Sexual dimorphism, like most other tetras, can be difficult to determine but males are often smaller and always slimmer in comparison with the females when viewed from above. Spawning is not easy to achieve. They are egg scatterers and require very soft and acidic water and darkness.

This fish is often commonly called the false neon tetra. The original description by Gery (1963) placed it in the genus Hyphessobrycon as H. simulans, "simulans" the Latin for similar due to the colour pattern similarity to the neon tetra. Fink & Weitzman (1977) placed it in the genus Paracheirodon [see below] with the two other neons, and subsequent DNA results have confirmed this placement. The Cardinal Tetra and the Green/False Neon have 26 and 25 chromosomes respectively, while the common neon tetra has 16.

In 1960, Dr. Jacques Gery erected the genus Paracheirodon for the type species P. innesi (Neon Tetra) and the Cardinal Tetra was also moved into the new genus. The name Paracheirodon derives from the Greek; the older genus Cheirodon means hand [cheir] and teeth [odon], and the prefix para means "beside" to distinguish Paracheirodon from Cheirodon. Paracheirodon was formerly considered within the Sub-Family Tetragonopterinae, but this classification is now deemed incertae sedis [Latin for "of uncertain placement"].

The presence of the "neon" blue/green lateral stripe readily identifies the neon tetra [Paracheirodon innesi], cardinal tetra [Paracheirodon axelrodi] and false or green neon tetra [Paracheirodon simulans], all of which are available in the hobby. A fourth "neon" species was discovered by Heiko Bleher in 2006 and has yet to be described and named. According to DNA studies, this new species is very close to the true Neon Tetra, whereas the Cardinal Tetra is genetically closer to the Green/False Neon Tetra.

Green Neon Tetra Diet

Carnivorous; will accept most commercially produced foods.


Maximum length 1.5 inches but usually much smaller, around 1 inch.

Minimum Tank Suggestion

24 inches in length

Ideal water parameters for Green Neon Tetra

Soft (less than 4 dGH) and acidic (pH 6.0 or below) water essential for long-term health, temperature 23-27C/73-81F. This species is sometimes found in the same waters as the cardinal tetra (termed sympatric) and both fish share identical water parameter requirements.

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