CHAPTER V.

_LUMP-SUCKERS, GOBIES, BLENNIES, BARRACUDAS, GREY MULLETS, STICKLEBACKS AND THEIR ALLIES, GARPIKE, AND FLYING-FISHES._

BY W. P. PYCRAFT, A.L.S., F.Z.S.

Ugly in appearance and carnivorous in habits, the Sucker-fish Family are distinguished by the presence of a large round sucker on the belly, with which they adhere to rocks. Furthermore, the sucker-fishes are remarkable for the softness of their skeleton, which may be cut through at any point with an ordinary knife. The male lump-sucker is smaller than the female, but much more brightly coloured, especially during the breeding-season, when he dons a livery of blue, scarlet, and yellow. He is also a model parent, always remaining near the eggs and keeping a constant stream of fresh water running over them by the action of his breast-fins. A single female may produce as many as 136,000 eggs in a single season. In Scotland the male is known as the COCK and the female as the HEN PADDLE. The species is more common off the coasts of Scotland than elsewhere in the British Islands.

Like the Lump-suckers, the GOBIES, which form the next family, have the ventral fins modified so as to form a sucking-disk, which is used as an anchor. But the gobies are easily distinguished by their smaller size, elongated bodies, hard skeleton, and the disposition and structure of the fins, characters which need not be discussed further.

One species, the SPOTTED GOBY, or POLE-WING, found in the Thames, is noteworthy on account of its nest-building habits. The male chooses the empty shell of a cockle or mussel, selecting one with its concave surface downwards. Beneath this the sand is cleared away and cemented by a special glue-like secretion formed by the skin of the fish. A cylindrical tunnel is then built to give access to the nest, and the whole is covered over with loose stones. In the nest-chamber formed by the shell the eggs are laid, the male immediately after mounting guard over them till they hatch, which they do in about nine days.

Another species, the PELLUCID GOBY, is remarkable in that its whole life's course is run in a single year. In June and July the eggs are laid; they are hatched in August; by the time winter has arrived the fish have reached maturity, and die off in the following July and August, so that in September only the fry are to be met with.

One of the strangest of all fishes is a member of the Goby Family. This is the WALKING-FISH, so called from its habit of spending most of its time on the mud-banks of rivers, or on the roots of trees growing in the neighbourhood. The late Surgeon-General Day, describing these fishes as he saw them along the side of the Burmese rivers, writes that at first sight they look like large tadpoles. When suddenly startled by something, away they go with a hop, skip, and a jump inland among the trees, or on the water like a flat stone or piece of slate sent skimming by a schoolboy. When climbing, the breast-fins are used, as if they were arms, to grasp the boughs. If placed in deep water, these fishes are speedily drowned!

The BLENNIES are fishes whose skins are soft, slimy, and quite scaleless, or at most covered with very tiny and degenerate scales. The general form of the body may be seen in the photograph below. They are shore-fishes, lurking about in the crevices of rocks, among seaweed, or under stones, and occurring generally along the coasts of temperate and tropical regions. The species known as the SEA-CAT or WOLF-FISH is, however, a deep-water form.

As a rule the eggs are deposited in hollow places between stones or rocks; but in the BUTTER-FISH, or GUNNEL, the eggs are adhesive, and the parents roll them into a ball by coiling their bodies round them. Furthermore, since the parents are frequently found, under natural conditions, coiled round these masses of spawn, it appears that they adopt this method of guarding their treasures. Some species bring forth their young alive.

The largest of the family is the WOLF-FISH, whose jaws are armed with very powerful teeth, able to crush the hardest shells, such as those of the whelk. Sea-urchins and crabs are also eaten.

We pass on to a group comprising three families--the BARRACUDAS, SAND-SMELTS, and GREY MULLETS.

It should be mentioned that two very distinct fishes are known as BARRACUDAS, one of which we have already described under the name of Snoek. The forms described here as barracudas are large, voracious fishes living in tropical and sub-tropical seas, and evincing a preference for the coast rather than the open sea. Attaining a length of 8 feet and a weight of 40 lbs., they are a source of danger to bathers. They are very frequently used as food, though in the West Indies such food is attended with some danger, as the flesh is often poisonous, from the fish having fed on smaller poisonous fishes.

The SAND-SMELTS are small carnivorous species inhabiting the seas of temperate and tropical regions. Many enter fresh-water, and some have become entirely acclimatised there. Some species bear a very close resemblance to the true smelt, from which, however, they may be readily distinguished by their small, spinous, first back-fin. The young of at least one small group or genus of this family are remarkable for their habit of clinging together for some time after they are hatched in dense masses and almost incredible numbers.

The GREY MULLETS are brackish-water fishes, feeding on vegetable growths and minute shell-fish. They also suck up large quantities of sand into the mouth for the sake of the minute organisms contained therein; much of this is passed on into the stomach, which is thick and muscular, like that of many birds. Altogether some seventy species of grey mullets are known, the majority of which attain a weight of about 4 lbs., but there are many which grow to 10 or 12 lbs. All are eaten, and some highly esteemed.

The FLUTE-MOUTHS, STICKLEBACKS, and TORTOISE-FISHES are three closely allied and extremely interesting families. The first are really gigantic marine sticklebacks, in which the jaws are produced into a long tube. They are shore-fishes, entering brackish water, and confined to sub-tropical and tropical parts of the Atlantic and Indo-Pacific.

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!

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.

The FLYING-FISHES, or FLYING-HERRINGS, like the Flying-gurnards already noticed, are enabled, by reason of the great development of the breast-fins, to take extended journeys through the air. The flight of these fishes is, however, not quite the same as true flight, inasmuch as the fins serve mainly as a parachute, and do not, by sustained vigorous movements, propel the body through the air, like the wings of bats and birds. Darting out of the water when pursued by an enemy or frightened by a passing vessel, these fish are borne along by the wind, the speed at first being very considerable, exceeding indeed that of a ship going ten miles an hour. At a single flight they may cover as much as 500 feet, but are quite unable to steer themselves, except when, during their course, the tail-fin is immersed in the water, when by a stroke from one side to the other the direction may be changed from left to right, or _vice versâ_, as the case may be. By day they will avoid ships, but by night, when they are unable to see, "they frequently fly," writes Dr. Günther, "against the weather-board, where they are caught by the current of air and carried upwards to a height of 20 feet above the surface of the water, while under ordinary circumstances they keep close to it."

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