Adrianichthyidae is a family that holds about thirty-two species of ray-finned fish, commonly known as ricefish, which can be found in murky and freshwaters from Japan to India, and in some Areas of the Indo-Australian Archipelago. The common name of this species is derived from the Japanese rice paddies where they are often found. Many of the ricefish species are endangered and it is thought that up to three may already be extinct, like the duck-billed Buntingi. It has been found that many species in this family, most notable the Japanese killifish, have been kept in personal aquariums since the seventeenth century.
Most species of ricefish are small, with the largest reaching 7.9 inches in length, so they are highly popular aquarium fish. Ricefish can be distinguished by their unusual jaw structure and the additional bone in their tail. They typically reproduce by spawning pre-fertilized eggs, although the Japanese killifish is known to develop its eggs inside its body until they are ready to hatch, after which time spawning occurs. Ricefish are noted as the first vertebrate to travel into space and successfully produce young and they are often the focus of studies in developmental biology.
Image Caption: Male Daisy’s Ricefish. Credit: Aquakeeper14/Wikipedia (CC BY-SA 3.0)