RED MULLET.
Not related to the Grey Mullets, this species is placed here for the sake of contrast.
Of the Sticklebacks there are several species, some of which are entirely salt-water fishes, whilst others enjoy the rather unusual distinction of being able to live in either fresh or salt water, even when rapidly transferred from one to the other. The small species commonly inhabiting ponds and ditches can sustain changes of this kind with impunity. These last are very ferocious. One kept in an aquarium devoured in five hours seventy-four young dace about a quarter of an inch long. They occasionally occur in vast shoals, and, according to the naturalist Pennant, appear in the river Welland, in Lincolnshire, once in seven years in amazing shoals, so that a man employed in collecting them earned four shillings a day by selling them at the rate of a halfpenny a bushel!
Photo by W. Saville-Kent, F.Z.S.] [Milford-on-Sea.
GARPIKES.
Frequently called Guard-fishes.
The salt-water species, or Fifteen-spined Stickleback, is less well known. Like its fresh-water relative, it is a nest-builder, and the male defends the eggs and young with great courage.
The Tortoise-fishes may serve as the representatives of the last family of this group. They are very remarkable fishes, being invested in a wonderful bony cuirass, formed by a modification of the skeleton, similar to what has taken place among the Tortoises and Turtles. The body is so thin that it looks as if it had been artificially compressed, and is semi-transparent. Three species are known from the tropical Indo-Pacific and three from other seas; besides these are four smaller and less perfectly armed forms, one of which, the Trumpet-fish, or Bellows-fish, occurs rarely off the south coast of England.
The Garpike and Flying-fishes are both interesting, especially the latter. The garpike is represented by several species, easily recognised by the long, pointed jaws. These fishes are furthermore peculiar in that the bones are green, a colour which remains even after cooking, and on this account some object to eating them, supposing the unusual colour to indicate unsoundness. The elongated jaws are not developed in the young fish, and, strangely enough, as this character is acquired, the lower jaw grows faster than the upper. In some species the lower jaw remains permanently the longer; hence they are known as Half-beaks.