Threadfin Rainbow

The Threadfin Rainbowfish (Iriatherina werneri), also known as the featherfin rainbowfish, is a small, peaceful freshwater nano fish native to tropical northern Australia and New Guinea. It is renowned for its long, flowing fin filaments and active schooling behavior.

Quick Facts

• Size:
  Grows up to 4–5 cm (1.5–2 inches) long, excluding the male's long tail extensions.

• Lifespan:
  3 to 5 years in a stable home.

• Origin:
  Found in slow-moving creeks, swamps, and billabongs in New Guinea and northern Australia.

• Behavior:
  Peaceful schooling fish that thrive in groups of 6 to 8 or more.

Aquarium Care

• Tank Size:
  Minimum of 15 to 20 gallons, preferably a longer tank to allow swimming space.

• Water Parameters:

  • Temperature: 24°C–30°C (75°F–86°F)
  • pH: 5.5–7.5
  • Hardness: 2–12 dGH

• Setup:
  Thrives in a heavily planted tank with dim lighting, dark substrate, and floating plants like duckweed.

• Tank Mates:
  Best kept with other tiny, peaceful fish or shrimp. Avoid aggressive or fin-nipping fish that could damage their long fins.

Diet and Feeding

• Mouth Size:
  They have very tiny mouths and throats, making them prone to choking on large food.

• Food Types:
  Feed micro-pellets, finely crushed flakes, baby brine shrimp, cyclops, and micro-worms.

This stunning fish is a perfect addition to peaceful, well-maintained aquariums, offering beauty and grace with its unique fins and schooling behavior.