What is "misgurnus fossilis"

Thunderfish \Thun"der*fish`\, n. (Zo["o]l.) A large European loach ( Misgurnus fossilis).

Misgurnis fossilis is a species of loach in the genus Misgurnus. It is commonly known as European weatherfish or European weather loach, due to its activity patterns changing when air pressure rises or falls. If there is a sudden change in barometric pressure, the weatherfish comes to the surface and swims about excitedly. In water with a low oxygen content it gulps air; it extracts oxygen through its intestinal mucous membrane, which has a complex system of blood vessels. It feeds on thawed frozen blood worms, small fish, brine shrimp, earthworms and some vegetables. It is quite an active loach and can grow to a length of 30 cm.