Small fish Cottus gobio found in fresh water
in the N hemisphere, often under stones. It
has a large head, a spine on the gill cover,
and grows to 10 cm/4 in. Related bullheads,
such as the father lasher Myxocephalus
scorpius, live in coastal waters. They are up
to 30 cm/1 ft long. The male guards the eggs
and fans them with his tail.