Japanese name: Shiro-uo

Scientific name: Leucopsarion petersii

Description: A small fish that's long and thin (up to 13 cm long), it is pale-fleshed, even transparent. Sometimes eggs can be seen through the body wall. The fish has an eel-like appearance, and some features, such as a straight digestive tract (rather than coiled) and the lack of a gastric gland in the adult, suggest that larval features are retained in this fish into adulthood. The eggs, the embryos and the larvae are also totally transparent.

Where to find them: In rivers in Kyushu and southern Honshu. Popular places for catching ice gobies are along the Matsumoto and Nishiki rivers in Kyushu.

Food: Marine plankton and algae. Although these fish adapt well to freshwater conditions, they do not feed on freshwater plants or animals.

Special features: Ice gobies spend most of their lives in the ocean, swimming up rivers into fresh water to breed, like salmon. When they transform into the freshwater form, they do not feed, but rely on energy reserves built up during life in the ocean to get them up the rivers to spawn. After spawning they die — that's if they are not caught by predators on the way, one of the most dangerous of which is man. Ice gobies are caught for food, and some people not only eat them raw, which is very common in Japan, but eat them alive, which is less common. For this delicacy, the living ice goby fetches a high price. It is sometimes called shirauo no odorigui (dancing icefish), and I like to think this is because of the squirming feeling of the living animal sliding down the throat ("dancing" is perhaps a bit fanciful — the fish is no doubt frantically trying to escape death). However one practical reason that ice gobies are eaten alive may be that they decay quickly once dead. Meanwhile, some fish have been reported showing nesting behavior. This is possible — many other species of fish construct nests for their eggs — and it may be the last thing they do after spawning and before dying.