Common Name: Forktail Blue-eye
Scientific Name: Popondichthys furcatu
Classification: Pseudomugilidae, Popondichthys
  • Size: 5-6 cm
  • Temperature: 24-28°C
  • pH: 7.0-8.0
  • GH: 90-180 ppm
  • IUCN: LR/LC (Lower risk/Least concern)
  • Country of Origin: It only lives in the streams between Dyke Ackland Bay and Collingwood Bay on the Papua Peninsula (also known as the Bird’s Tail Peninsula) of Papua New Guinea.

Popondichthys furcatu is the genus, Popondetta, described by Gerald R. Allen in 1980; Pseudomugil furcatusfrom the original genus, Popondetta, was classified into Popondetta furcatus; Popondetta connieae was described as the second species of the genus. This species is restricted to the area between Popondetta and Safia of the Papua Peninsula. Allen considered Popondetta as a species different from Pseudomugil because there are more rays on its anal fin (16-20 vs. 8-12), no anterior projection in the ventral center of its pelvic girdle, and no distinct scale radii. However, the name, Popondetta, was already used on an insect genus under Hemiptera: Lygaeidae in 1978; according to Article 23 of the International Code for Zoological Nomenclature, the first publisher has priority in naming. Hence, Popondetta was invalid as the new genus name under Pseudomugil. Allen proposed another name, Popondichthys, in 1986; meanwhile, he, B. Said, and W. Ivantsoff from Macquarie University in Sydney studied the relation within Melanotaeniidae. The preliminary result they acquired is that Popondichthys may be a subgenus under Pseudomugil, so in 1989 P. furcatus and P. connieae were classified into Pseudomugil However, in 1997, Ivantsoff and Allen elevated Popondichthys to a valid genus based on morphological differences and moved Pseudomugil furcatus back to the genus, becoming the only valid species in the genus and being used until today.

However, in the aquarium market, Forktail Blue-eye is still called by its old scientific name, Pseudomugil furcatus. The body color of this species is mainly yellow and translucent and its abdomen appears to be orange; its dorsal, pectoral, and anal fins are transparent, but the edges of each fin are bright yellow. The caudal fin of the female Forktail Blue-eye appears to be pale yellow, and the pectoral and pelvic fins are transparent, which is not as bright and beautiful as the male ones.