Aquarist Atlas
Aquarist Atlas · the ricefishes

Ricefish

The ricefishes and medaka — the family Adrianichthyidae — are small, surface-feeding fish of the fresh and brackish waters of South, Southeast and East Asia. The family has 46 valid species under the Catalog of Fishes, mostly in the genus Oryzias. The largest radiation is on Sulawesi, where species are endemic to single lakes such as Matano, Towuti and Poso, and where several are pelvic brooders: the female carries her fertilised eggs on her body for a time before depositing them. The Japanese medaka, Oryzias latipes, has been kept in ponds and aquariums for a long time and is a laboratory model organism. In the hobby, Oryzias woworae from Muna Island is the popular “Daisy’s ricefish”. This section is built to the same standard as the cichlid, cory and pleco pages: researched, cited accounts with no Wikipedia and no invented facts.

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Most ricefishes are easy, small fish for a planted tank. Species differ in what they need, so check the species page, but a few points hold across the family. Temperature: the East Asian medaka tolerate a wide seasonal range and often do well unheated, while the tropical Sulawesi and Southeast Asian species are kept at normal tropical temperatures. Water: the Sulawesi lake species come from hard, alkaline water and do better in it than in soft water. Cover: floating plants and fine-leaved plants give the fish security, and many species spawn by depositing eggs on them. Tankmates: ricefishes are small and peaceful, so keep them with other small, gentle fish. Some species have a very small wild range, and a captive-bred, well-documented line is worth more than another wild collection.

46 species in the atlas

We cover the whole family Adrianichthyidae: all 46 species valid under the Catalog of Fishes, in the genera Oryzias, Adrianichthys, Horaichthys and Nasutoryzias, from the Japanese medaka to the Sulawesi lake endemics. Each species page states whether its size is given as standard length or total length.

Species

46 of 46 species

Sulawesi ricefish · 25

The Sulawesi radiation, the family's largest group: ricefishes of the island's lakes (Matano, Towuti, Poso and others), rivers and streams, found nowhere else. Several are lake specialists, and many of these species are pelvic brooders, the female carrying her fertilised eggs on her body for a time before depositing them. Genera Oryzias and Adrianichthys.

Mainland South & Southeast Asian ricefish · 11

Ricefishes of the mainland, from the Indian subcontinent through Myanmar, Thailand, Laos, Cambodia and Vietnam: fish of rice paddies, ditches, ponds and the quiet margins of rivers, some in brackish coastal water. Includes the tiny Oryzias minutillus and the monotypic Horaichthys, whose males carry a modified, fin-based copulatory organ.

East Asian medaka · 6

The medaka of Japan, Korea and China. Oryzias latipes, the Japanese medaka, is a long-kept pond and aquarium fish and a laboratory model organism; its relatives here include O. sakaizumii and several recently described Chinese and Taiwanese species.

Island Southeast Asian ricefish · 4

Ricefishes of the Philippines, Java and the Lesser Sunda islands: lowland fish of ponds, streams, estuaries and brackish water, such as Oryzias luzonensis, O. javanicus and O. timorensis.

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