Paracheirodon simulans
False neon tetra
(Also: Green neon tetra; Green tetra; Neon; Neon tetra)

Paracheirodon simulans is native to the neotropical region. These fish, which are commonly called green neon tetras, are found in northwest Brazil to Colombia in the River Negro, and in Venezuela in the upper Orinoco River basin. ("Aquaria Central", 1997; Binohlan and Casal, 2003; "Paracheirodon simulans (Green Neon Tetra)", 1998; Robins, et al., 1991)

Paracheirodon simulans is mainly found in black water rivers of the South American tropics. They have been found in northwest Brazil in the River Negro to Colombia and Venezuela in the upper Orinoco River basin. Temperatures in these waters range from 72 to 82 degrees F. Because these jungle waters are typically shaded by overgrown trees, when keeping green neon tetras in captivity it is best to duplicate this natural shading by making the sides and bottoms of the aquarium dark. ("Aquaria Central", 1997; "Paracheirodon simulans (Green Neon Tetra)", 1998)

Green neon tetras appear similar to neon tetras, Paracheirodon innesi, although they are smaller and the red patch on the lateral body is less pronounced. The lateral blue-green stripe extends to the base of the caudal fin. These fish can grow to a maximum overall length of approximately 2.5 cm. ("Aquaria Central", 1997; "Wikiverse", 2004)

The pattern of development in these animals has not been characterized. However, eggs of P. axelrodi generally develop within 24 to 30 hours of fertilization. (Gilbert, 2003)

Paracheirodon species generally spawn in schools, although single males and females may become closely associated while the female releases her eggs and the male releases his sperm.

Information on reproduction in tetras comes from specimens housed in aquaria. Female neon tetras lay approximately 130 eggs on the substrate. Fry hatch in about 24 hours. These fish tend to breed every few weeks. The larvae of these fish are sensitive to ultraviolet radiation, so are restricted in the areas in which they may lay their eggs. Generally, eggs are left under canopies to ensure they hatch. Eggs are typically laid during the rainy and wet seasons when water levels are higher. ("Aquaria Central", 1997; Binohlan and Casal, 2003)

Once eggs are laid, adult tetras do not provide any further parental care. Adult tetras may even eat their eggs and larvae. ("Aquaria Central", 1997; Binohlan and Casal, 2003)

The longevity of green neon tetras has not been reported.

There is little information on the behavior of P. simulans. They are typically found in schools of 6 fish or more. These are also thought to be the schools within which they mate. Small localized migrations may take place in response to changing water levels. ("Aquaria Central", 1997; "Paracheirodon simulans (Green Neon Tetra)", 1998)

Home ranges of these animals in the wild hav not been reported.

Green neon tetras transmit sound energy to the auditory organ by the use of a Weberian apparatus. This structure allows these fish to have better hearing characterized by large bandwidths and high sensitivity. (Hertwig and Schneider, 1999)

In addition to their hearing, green neon tetras have eyes, and can perceive visual signals, although the role of such signals in their commmunication has not been documented. Tactile communication may have some role in mating.

Paracheirodon simulans is omnivorous. These fish tend to eat small live foods such as crustaceans, fish larvae, and insects. ("Paracheirodon simulans (Green Neon Tetra)", 1998)

Patterns of predation on these animals in their natural habitat have not been reported. However, it is likely that they are eaten by larger fish and other larger, aquatic predators at all life stages. The structural color that makes up their neon stripes may help to confuse predators and make it more difficult to catch these small fish. They are also protected from predators to some extent through their schooling behavior.

The role of P. simulans in its ecosystem has not been investigated. Green neon tetras act as important predators on their small, invertebrate prey, and serve as important food sources for larger, aquatic predators.

Green neon tetras, and neon tetras in general, are important in the pet trade. They are popular for their bright coloration. ("Aquaria Central", 1997)

Paracheirodon simulans has no reported adverse effect on human economies.

Paracheirodon simulans is not listed by CITES or IUCN as a conservation concern. This species is common within their native range and widely used in the pet trade.