Paracheirodon Simulans (Green Neon Tetra)

Paracheirodon simulans (“Green Neon Tetra”)

Paracheirodon simulans is a brilliant, small schooling tetra native to the upper Rio Negro and Orinoco River basins in South America. Closely related to the more common Paracheirodon innesi and P. axelrodi, this species is distinguished by its intense turquoise-green iridescent stripe and smaller size. It inhabits slow-moving, shaded blackwater tributaries rich in tannins and leaf litter. Peaceful, active, and highly social, the Green Neon Tetra makes an exceptional choice for blackwater and planted aquariums.

Size:
Adults reach approximately 2.5–3.5 cm (≈ 1.0–1.4″) in length.

Water parameters:
Very soft, acidic blackwater is ideal.
pH 4.5 – 6.5
GH ≤ 4 °d
KH ≤ 2 °d
TDS < 100 ppm
Provide stable, clean water with minimal current, subdued lighting, and natural décor such as driftwood, botanicals, and leaf litter to replicate their forest-stream habitat.

Temperature:
24 – 28 °C (75 – 82 °F); stable warmth enhances coloration and vitality.

Food:
Omnivorous micro-predator. Offer high-quality micro-pellets, crushed flakes, and small live or frozen foods such as daphnia, baby brine shrimp, and cyclops. A varied diet helps maintain their brilliant green-blue sheen.

Tankmates:
Extremely peaceful and best kept in schools of at least 8–10 individuals.
Suitable companions include other small, gentle blackwater species such as Hyphessobrycon amapaensis, Boraras, Corydoras pygmaeus, or dwarf apistogrammas.
Avoid large or aggressive fish that may intimidate or outcompete them.

Breeding:
A challenging species to breed. Requires very soft, acidic water and dim conditions.
Use a separate breeding tank with fine-leaved plants or spawning mops.
Eggs are scattered among plants; remove adults afterward to prevent predation.
Eggs hatch in 24–36 hours; fry are delicate and should be fed infusoria or green water until large enough for baby brine shrimp.

Important note:
Paracheirodon simulans originates from highly specialized, tannin-rich blackwater environments.
They are sensitive to sudden changes in pH or hardness and should only be introduced to a mature, stable aquarium.
They thrive in calm, low-light conditions with soft water and do best in well-established, planted systems.