M. C. W. Weber, 1913
|Sub-families & Genera|
The ricefishes are a family (Adrianichthyidae) of small ray-finned fish that are found in fresh and brackish waters from India to Japan and out into the Indo-Australian Archipelago, most notably Sulawesi. The common name of the group derives from the fact that many species are found in Japanese rice paddies. This family consists of about 32 species, some extremely rare and endangered, and some 2-4 may already be extinct.
Most of these species are quite small, making them of interest for aquaria. The largest species, the buntingi, can reach 20 centimetres (7.9 in) in length, but most are less than a fifth this length, with the smallest being only 1.7 centimetres (0.67 in) long. They have a number of distinctive features, including an unusual structure to the jaw, and the presence of an additional bone in the tail. The medaka, Oryzias latipes, is a popular model organism used in research in developmental biology. Ricefish have traveled into space, where they have the distinction of being the first vertebrate to mate and produce healthy young in space.
Genetic study of the family suggests that it originally evolved on Sulawesi and spread from there to the Asian mainland; the supposed genus Xenopoecilus are apparently unrelated, morphologically divergent species of Oryzias.
Ricefish are believed to have been kept as aquarium fishes since the 17th century. O. latipes has been one of the oldest species to have been kept and has been since bred into a golden color, from their original white coloring.
As with most fish, ricefish typically spawn their eggs, which are fertilised externally. However, some species, including the medaka, are known to fertilise the eggs internally, carrying them inside the body as the embryo develops. The female then lays the eggs just before they hatch. Several other species carry their eggs attached to the body between their pelvic fins.
- Parenti, Lynne R. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 152. ISBN 0-12-547665-5.
- Takehana et al., 2005
- Froese, Rainer, and Daniel Pauly, eds. (2008). "Adrianichthyidae" in FishBase. November 2008 version.
- Takehana, Yusuke; Naruse, Kiyoshi & Sakaizumi, Mitsuru (2005): Molecular phylogeny of the medaka fishes genus Oryzias (Beloniformes: Adrianichthyidae) based on nuclear and mitochondrial DNA sequences. Molecular Phylogenetics and Evolution 36(2): 417–428. doi:10.1016/j.ympev.2005.01.016