The threadfin rainbowfish, scientifically known as Iriatherina werneri, is a captivating species belonging to the rainbowfish family. It is the sole member of the Iriatherina genus and is renowned for its long, exquisite fins, making it one of the most visually appealing rainbowfish.
This species is native to freshwater swamps, demersal areas, and densely vegetated regions of flowing waters in tropical northern Australia and New Guinea. It typically reaches a length of up to 5 cm (2.0 in), excluding the Threadfin's elongated tail. Distinguishing between males and females is relatively simple by examining their fins: males possess larger and more flamboyant finnage compared to females. Additionally, males exhibit more vibrant colors, enhancing their aesthetic appeal. During reproduction, the female scatters eggs among submerged vegetation, and they hatch after 7-10 days.