Parrotfish make themselves a kind of mucus 'sleeping bag' which masks their smell from predators and keeps parasites away.
4
There is a disease called ichthyosis that turns the skin scaly like a fish.
90
The seahorse is the only fish to have a neck.
12
On some poorly researched trivia lists it is stated as a fact that a pregnant goldfish is called a twit. This is not true as goldfish lay eggs.
71