Threadfin Rainbow - Iriatherina werneri

SKU: 208555
Manufacturer: That Fish Place
MPN: F90 0022 0477

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Threadfin Rainbowfish (Iriatherina werneri) are very interesting and unique rainbows. Females are pale gold overall with some faint accents and slender bodies. Males feature a pale gold color with possible reddish or yellow accents (a male is pictured above). The finnage is what makes these rainbows so stunning. Like most rainbows, these have double dorsals. The first dorsal is very high and fan-shaped. The second dorsal has elongated filaments. The anal and pelvic fins also feature elongated filaments, usually dark red to black in color. The caudal fin is deeply v-shaped and features elongated filaments, as well. The female may feature some of the same colors and fins, though much more subdued.

Rainbow fish make a great additions to a community tank. Their sleek, oblong bodies are made for speed, and they constantly make laps back and forth through the aquarium. Many species grow to 3 to 4 inches in length and a small group of these fish can add extraordinary color to your tank. While juveniles may have a relatively drab appearance, they truly live up to their name as they mature. Males are especially colorful in most species, developing vibrant yellow, orange, red, blue and green shades, some with stripes or bars. Both males and females should be kept in the aquarium so males retain their vibrant hues. Rainbows are schooling fish, and it is best to keep them in groups of at least four so they feel secure and stay in the open.

New species and variations of Rainbowfish are being discovered and imported for aquarium use each year as they gain in popularity. The largest and most well-known genus is Melanotaenia, and species from genus Pseudomugil are also frequently offered. Other less common species may also be seen in our tanks from time to time. Most Rainbowfish originate in lakes, streams and rivers of Australia, Southeast Asia, and other islands in the region.

Rainbows can be kept with a wide variety of community tank mates like tetras, danios, rasboras, others Rainbows, dwarf cichlids and similar fish. They are not picky eaters and will generally accept flakes, pellets and a range of frozen foods like mysis, brine shrimp and other similar items. They will not bother plants and are ideal for planted aquariums. A long aquarium is best to give them plenty of distance to swim back and forth in the tank.


F90 0022 0477
That Fish Place
Common NameThreadfin Rainbow
Scientific NameIriatherina werneri
OriginNew Guinea, Australia
Max Size (in inches)1.5
Community SafeYes
pH Range6.5-7.5
Min Tank Size (in gallons)15
Temperature Range75-82
Internal Id

State Restrictions
Armed Forces Americas
Armed Forces Europe
Armed Forces Pacific
Puerto Rico


Ratings & Reviews

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Great fish, can be tricky to feed


These are great little community fish! The males will often "display" to females or other males by shaking their fins out full length, and they make for rather impressive displays. The tricky part about keeping these fish is their mouth - they have TINY little mouths, and require tiny live foods or finely crushed flake food to survive. It seems like they do better on frequent, small feedings than large, occasional feedings, too.



I have 11 of these amazingly eye catching fish! I wish I knew about them earlier in my fish keeping hobby because they would have been the main thing in Mt 2 29 gallion tanks. Not that they still can't be but I love how they have captured me by heart. A MUST HAVE AND EASY, FUN, FISH TO KEEP!!! I hear they are easy to breed, I hope