Papuan Threadfin Rainbowfish — a Melanotaeniidae from N Australia & New Guinea, peaceful schooling fish; males shimmer and spar gently. Reaches 3–4.4 cm; groups of 6–8 minimum; larger schools calm them. 26–30 °C.
Care parameters
Water temperature
26–30 °C
pH
6–8
GH hardness
5–12 dGH
Adult length
3–4.4 cm
Minimum tank
25 L
Water layer
Bottom-dwelling
Difficulty
Moderate
Temperament
Peaceful schooling fish; males shimmer and spar gently
Origin
N Australia & New Guinea
Species overview
Iriatherina werneri is a Melanotaeniidae from N Australia & New Guinea. Its iridescence is honest signalling: colour and condition track water quality and age together. It lives on the bottom. Adults reach 3–4.4 cm. Groups of 6–8 minimum; larger schools calm them. Provide swimming length, clean hard water and a big school; patience does the rest. Maintain 26–30 °C at pH 6–8. A solid choice for a well-planned community tank.
Native biotope
Habitat
Warm freshwater streams and lakes
Flow
Still to gentle current
Dissolved O₂
Moderate oxygen levels
Aquascape & hardware
Substrate
Fine sand and gravel
Hardscape
Driftwood and smooth stones
Plants
Hardy common aquarium plants
Temperament, diet & tankmates
Schooling
Groups of 6–8 minimum; larger schools calm them
Diet
Omnivore; quality flakes plus vegetable matter
Recommended tankmates
Robust peaceful cyprinids — Add motion without menace
Avoid keeping with
Small timid fish — Outcompeted at feeding time
Breeding & notes
Sexual dimorphism
Subtle external differences
Breeding method
Prolific egg-scatterer when kept hard and alkaline