Fresh water fish in Kochi : Donko

by M. Takano

Odontobutis obscura is called “donko” in Japan. But it is also known as cozikimara (Shiga Prefecture), doroboume and dokan (Kinki district), ushihustu (Wakayama Prefucture), Donpo (Nagasaki Prefucture) and Gomo Anagomo in various places in Japan. The generic family of Donko is gobioidei . Among the  Gobioidei of Japan, donko are rare fresh water fish.

Description & Taxonomy & Range

Donko can be as big as 25 centimeters in diameter. They are larger than other Gobioidei fresh water fish in Japan. The head is bigger other Gobioidei. The mouth is big and the lip is thick. There are fine teeth on an upper and lower jaw. Pectoral fin has evolved. The pelvic fin has divided into two sections and Coloring is Brown. They are classified into the Odonto butidae family Perciformes. This specie is set as type species of the Odontobutis Bleeker ,1876 from East Asia. In old times,the population distributed around Japan to be a kind. But there are five groups in Japan: “Yamakage, Biwa, Ise, Hitomi, Higashisheto , Nishiseto, Nishikyuusyuu, Hitomi group became “Odontobutis”

Ecology

They live in rivers, lakes, ponds, rice paddies and irrigation canals. Donko like places where water flows gently , and spends all its life in a fresh water environment. They live alone and are territorial. They are Nocturnal, and in daytime, Donko live under the rock or water plant. They  are predacious  to small fish, aquatic insects and crustacean, but don’t react to the one that doesn’t move. The breeding time is July flow April. The female lays in the nest, and the male looks after the eggs. There is a brood parasitism situation too. The fly that hatched is already big . Of  the fresh water Gobiodei, there are three varieties in Japanese: “Donko’’ “Ishidonko’’and “Kawayoshinobori.’’

Use & Conservation

Donko are sometimes, though rarely, used for food. The cooking method the fry without coating and the salt scorch. And, meat is white meat and so very delicious. But as a rule, they are not eaten raw. They are likely to be kept as a pet. since they are comparatively easy to care for. The habitat of Donko is decreasing now due to the pollution of water.

Viewing

If you would like to swim in rivers, try the Niyodo or Shimanto rivers in Kochi. The Donko live in the bottom in the river welcome you at that time. And if a Donko fish nibbles your foot, it means good luck!