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Threadfin Rainbowfish – Iriatherina werneri

Threadfin Rain­bow­fish – Iriathe­ri­na werneri is a beau­ti­ful, peace­ful fish. The com­mon names, Threadfin and Feath­erfin, describe the ele­gant fins of the mature male. Their fins are long and sweep­ing, show­ing gor­geous extend­ed fil­a­ments on their dor­sal fins. They con­trast beau­ti­ful­ly against the var­i­ous shades of greens in a nature aquar­i­um.

Com­mon Name: Threadfin Rain­bow­fish

Sci­en­tif­ic Name: Iriathe­ri­na werneri

Typ­i­cal Adult Fish Size: 1.5 inch­es / 4 cm

Care Lev­el: Inter­me­di­ate

Nat­ur­al Habi­tat: They are found in Indone­sia, New Guinea and North­ern Aus­tralia. Threadfin rain­bow­fish inhab­its clear, slow mov­ing water­ways, lagoons and grassy swamp areas.

Ideal Tank: They enjoy a peace­ful com­mu­ni­ty aquar­i­um. Threadfin rain­bows are a per­fect addi­tion to a nature aquar­i­um (plant­ed tank). Remem­ber when you are hous­ing cap­tive bred Threadfin Rainbow’s, it is vital to pro­vide them with a long aquar­i­um that has sec­tions with lush plants. These fish absolute­ly love and need plen­ty of space for their active swim­ming habits. They are also well known jumpers. Keep­ing your aquar­i­um cov­ered ful­ly will pre­vent these fish from jump­ing out.

Tank Size: 30 gal­lon

Tank Mates: Peace­ful com­mu­ni­ty tank mates like Mol­ly, Gup­py, Platy and Tetra.

Aquar­i­um Water Tem­per­a­ture: 23 – 32°C (73 – 89°F)

Aquar­i­um Water pH: Range pH 4.5 – 7.5

Feed­ing: When feed­ing any fish, foods should be con­sumed after a few min­utes. Any food that is left­over in the aquar­i­um should be removed with a fine fish net as it will cause prob­lems in your water con­di­tions and the integri­ty of your fish. A trop­i­cal flake food diet is a great base food for the Rain­bow. With the addi­tion of live foods it will ensure the best pos­si­ble health and longevi­ty of your fish. Live or frozen brine shrimp, blood­worms, fruit flies, micro worms, mos­qui­to lar­vae, diced Earth­worms, daph­nia are all great foods to con­sid­er for their diet. It is always good to pro­vide dif­fer­ent types of food for their nutri­tion intake. Good food = healthy, vibrant fish.

Sex­ing: Adult males boast extend­ed pelvic fins. They are larg­er and more col­or­ful than females.


Oth­er Con­sid­er­a­tions: A pop­u­lar fish for hob­by­ists. They should not be added to an aquar­i­um that is not cycled or that is still cycling. Prefer­ably an estab­lished tank for best results.