The sea-horse is not the fish that we know today, but a mythical, chimeric creature composed of the upper part of a horse and the tail of a fish. It occurs as a supporter but also in the arms of some sea-faring families and towns, and also, somewhat oddly, in the arms of the (inland) university town of Cambridge! A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Sea-horse