The Threadfin Rainbowfish (Iriatherina werneri) is a small, unique species of rainbowfish characterized by their extremely long fins and lovely black and red colouration. This listing is for juvenile specimens, ~1 inch long.
Threadfin rainbowfish stay very small, generally within 2 inches in length, making them a great choice for nano-aquarium as small as 10 gallons. These fish prefer to live in shoals, and we recommend keeping them in groups of 3+ (the bigger the group, the better).
These animals require a water temperature between 73-81 degrees Fahrenheit, and do best in a pH between 5.0 and 8.0. While these fish are relatively hardy, they can quickly succumb to water quality issues. Never put these fish in a new, uncycled aquarium. These fish are best suited for a fully planted aquarium and tend to do better in tanks with plenty of hiding spaces. These fish do best in water with a low flow. A tight-fitting, secure lid is heavily recommended.
Threadfin Rainbowfish are generally docile and can be kept with other docile fish species. Do not put these fish in with tankmates that are prone to fin-nipping, or are generally very energetic (as Threadfin Rainbowfish have long fins, and will be out-competed for food by fast tankmates). These rainbowfish can be kept with dwarf shrimp, such as Cherry shrimp, with no issues.
Feeding this species is easy. They are omnivores and will accept a wide variety of food. They can be fed pellets and flakes, as long as they are crushed into a powder first. They can eat small frozen and live food specimens too, such as baby brine shrimp. These fish display the best colouration when fed a high-quality, varied omnivore diet.
(Photo credit "Home of the Rainbowfish")