Javan Ricefish

About

The Javan ricefish (Oryzias javanicus) is a small, infrequently traded species from the shallow, plant-choked ditches, canals, and ponds of Indonesia, Malaysia, Singapore, and Thailand, with records also from the Mekong basin. It belongs to the family Adrianichthyidae, the ricefishes, which are more closely related to needlefish and halfbeaks than to the toothcarps they superficially resemble. Physically, the species is compact and deep-bodied for a ricefish, with a squared-off tail fin rather than the lunate or notched shape seen in several close relatives. Both lobes of the caudal fin carry yellow submarginal bands, and the eyes have a blue sheen that gives the fish one of its occasional trade names. In the wild it feeds at the surface on insects, small crustaceans, and protozoans, and aquarium specimens do best on similarly meaty small foods. The species is listed as beginner-level in care, though it has a reputation for being tricky to keep in good long-term health, so some research is worthwhile before sourcing them. Males can squabble with each other during courtship, and breeding groups of eight or more tend to behave more naturally and confidently. Spawning behavior is genuinely interesting. Females carry adhesive egg masses externally before depositing them among fine-leaved plants. Crossing with other Oryzias species is documented, so avoid mixing congeners if you plan to breed them.