Threadfin Rainbowfish

The Threadfin Rainbowfish(Iriatherina werneri) is an ethereal and elegant addition to the aquarium, famous for the long, feathery fin extensions that give them their name. They grow up to 5 cm long, and while their bodies are slim and silver, the males put on a spectacular display by “flashing” their elaborate, fan-like dorsal and anal fins to attract females.They thrive in habitats with plenty of hiding spots.

While you can keep at six and up, we strongly suggest a group of 10–15 threadfin rainbowfish with a higher ratio of females to males. This setup encourages the males to display their stunning finnage without excessive competition.

Threadfins are semi-peaceful, tolerate harder or softer water, the trick is to have a well cycled tank with these guys. We sell our Threadfin Rainbowfish young and the males will later develop their stunning longer fins that they flex and display so stunningly when courting the females also. Threadfins can get stressed easily, shoal, and need cover to feel secure. Planted tanks recommended.

Threadfin Rainbowfish are NOT RECOMMENDED WITH DISCUS as they prefer a warmer water temperature. They are happiest with water temperatures between 23 – 26°C. Avoid housing them with fast-swimming or “nippy” tank mates, like certain Barbs or Tetras, which may damage their delicate, trailing fins. Because they have very small throats, they cannot eat standard-sized pellets or large flakes. Since they like to swim in the middle and upper levels of the tank, try feeding very fine, suspended foods. Their favourite meals include baby brine shrimp, daphnia, and finely crushed flakes.