Upper Negro and Orinoco River basins: Brazil, Colombia and Venezuela.

South America: Upper Negro and Orinoco River basins.

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.

Biogeographic Regions: neotropical (Native )

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.

Range length: 2.5 (high) cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Maximum size: 35 mm TL

2.0 cm SL (male/unsexed; (Ref. 38376))

Paratype for Paracheirodon simulans
Catalog Number: USNM 197510
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Collector(s): H. Schwartz
Year Collected: 1962
Locality: Brazil: Amazonas, Lower Rio Purus,, Amazonas, Brazil, South America

pelagic; freshwater; pH range: 5.5 - 6.0; dH range: 4

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.

Habitat Regions: tropical ; freshwater

Terrestrial Biomes: rainforest

Aquatic Biomes: pelagic ; rivers and streams

Paracheirodon simulans is omnivorous. These fish tend to eat small live foods such as crustaceans, fish larvae, and insects.

Animal Foods: insects; aquatic crustaceans; zooplankton

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)

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.

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.

Known Predators:

• larger fish (Actinopterygii)

Anti-predator Adaptations: cryptic

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.

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.

Communication Channels: acoustic

Perception Channels: visual ; acoustic ; vibrations

Spawns better in schools than pairs.

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.

The longevity of green neon tetras has not been reported.

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.

Mating System: polygynandrous (promiscuous)

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.

Breeding interval: Green neon tetras breed every few weeks.

Breeding season: Breeding season in the wild is influenced by water levels, generally occurring during rainy seasons. In captivity these fish can reproduce at any time of year.

Average number of offspring: 130 eggs.

Average time to hatching: 24 hours.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Once eggs are laid, adult tetras do not provide any further parental care. Adult tetras may even eat their eggs and larvae.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1

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.

US Federal List: no special status

CITES: no special status

Not Evaluated

aquarium: commercial

Paracheirodon simulans has no reported adverse effect on human economies.

Green neon tetras, and neon tetras in general, are important in the pet trade. They are popular for their bright coloration.

Positive Impacts: pet trade