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Threadfin Rainbowfish care guide

Threadfin Rainbowfish (Iriatherina werneri) — minimum tank 40 L, temperature 24-30 °C, pH 5.5-7.5.

Overview

The Threadfin Rainbowfish (Iriatherina werneri) is a small melanotaeniid from northern Australia and New Guinea. Males display dramatically elongated thread-like dorsal and anal fin rays; both sexes show subtle iridescent body colour.

Taxonomy

  • Family: Melanotaeniidae
  • Genus: Iriatherina
  • Scientific name: Iriatherina werneri
  • Common synonyms: Featherfin Rainbowfish

Habitat

Native to vegetated swamps, billabongs and slow-flowing creeks of northern Australia (Cape York Peninsula) and southern New Guinea, in warm, soft to moderately hard, slightly acidic to neutral water.

Tank requirements

  • Minimum tank volume: 40 L (10.6 US gal)
  • Adult size: 3-4 cm
  • Temperature: 24-30 °C (75-86 °F)
  • pH: 5.5-7.5
  • GH: 3-12 °dGH
  • Water flow: low
  • Lifespan: 3-5 years
  • School size: ≥6 individuals

Diet

An omnivore with a small mouth. Offer finely crushed flakes, micro-pellets and small live or frozen foods (cyclops, daphnia, baby brine shrimp).

Compatibility

A peaceful, delicate shoaling species. Keep a group of at least six in a heavily planted aquarium with subdued lighting and gentle flow. Avoid all fin-nipping species (barbs, Serpae Tetra) and very active tankmates; ideal companions are calm nano fish such as Boraras, Ember Tetra and dwarf rasboras.

Breeding

An egg-layer that places adhesive eggs on fine-leaved plants or spawning mops over several days. Eggs incubate for 7-12 days; fry are tiny and require infusoria as a first food.

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