CHAPTER III.

_SCALY-FINS, RED MULLETS, SEA-BREAMS, SCORPION-FISHES, SLIME-HEADS, TASSEL-FISH, MEAGRES, AND SWORD-FISHES._

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

For quaintness of shape, combined with beauty of coloration, the family of Scaly-finned Fishes has no rivals. The name by which they are collectively known refers to the scaly covering which invests the bases of what are called the median fins--the fins seated along the middle of the back and abdomen. A large number of distinct species have been described, the majority of which occur in tropical seas, and especially in the neighbourhood of coral-reefs; but some frequent the mouths of rivers, which they occasionally ascend for a short distance. All are of relatively small size, of carnivorous habits, and but little used for food.

The pattern of coloration commonly takes the form of bands or stripes, those in which this pattern is most marked being known as ZEBRA-FISH. One of the most beautiful is the EMPEROR-FISH, which ranges from the east coast of Africa to the Indian and Malayan seas. The ground-colour of the body is deep blue, relieved by some thirty golden-yellow stripes running from the shoulder backwards to the tail. Crossing the head is a crescent-shaped bar of black edged with yellow, whilst a similarly coloured patch runs upward from the pectoral fins to within a short distance of the top of the back. This species, which attains a length of 15 inches, is highly esteemed for food in India. The most beautiful of all, perhaps, is the zebra-fish of the Indo-Malayan seas, which has the ground-colour of yellow, striped with vertical bars of blue edged with brown, a yellow tail, and an anal fin barred with narrow blue lines.

A tubed-shaped mouth is a common feature of the fishes of this group, and two Indian species in which this character is especially well developed have acquired the habit of shooting therefrom a drop of water at insects resting on overhanging foliage fringing the sea or along the banks of rivers. Having sighted its quarry, it would seem the fish moves upwards to the surface of the water, and with careful aim ejects its liquid bullet with such unerring precision that its prey is invariably knocked down and speedily seized. On this account these fishes are commonly known as ARCHER-FISHES. The archer-fishes are sometimes kept in tubs of water, for the purpose of affording amusement to their captors. Somehow the shooting prowess of these fishes has been accredited to an allied form, shown in the above photograph.

The peculiar shape of these fishes is sufficiently indicated by the photograph already mentioned, but a large series would be necessary to show the numerous variations, some of which are quite remarkable. The brilliancy of the coloration is probably protective, since the most brightly coloured forms live amongst coral-reefs built by gorgeous polyps, or coral-animals, so that amidst such surroundings the fishes are quite inconspicuous.

The RED MULLETS occur chiefly in tropical seas, but one species inhabits European waters, and occur sparsely around the British Islands. Occasionally, however, these fishes visit the British coasts in vast shoals, more than 5,000 having been taken in a single night in August, 1819, in Weymouth Bay, whilst in May, 1851, 10,000 were taken off Yarmouth in one week.

Although about forty species of red mullet are known, the European species is the most prized as a food-fish. Its fame, indeed, extends backwards to the time of the ancient Romans, who sought far and wide for large specimens, paying ruinous prices for them. "Then, as nowadays," writes Dr. Günther, "it was considered essential for the enjoyment of this delicacy that the fish should exhibit the red colour of its integument. The Romans brought it, for that purpose, living into the banqueting-room, and allowed it to die in the hands of the guests, the red colour appearing in all its brilliancy during the death-struggle of the fish. The fishermen of our times attain the same object by scaling the fish immediately after its capture, thus causing a permanent contraction of the chromatophores containing the red pigment."

Beneath the chin of the red mullets will be noticed two long finger-like processes; these can be thrust forward and moved about, or laid back in a groove between the sides of the lower jaw, and are used to rake about in the sand and gravel at the bottom of the sea to discover burrowing shrimps or worms. Even dead food they are said to feel with these barbels, as they are called, before biting. The red colour has been observed in the Marine Aquarium at Plymouth to become darker when the fish rise from the ground, and to pale away when they descend.

Two forms of red mullet occur in European waters, but it is not yet finally settled whether they represent distinct species. The one is the plain RED MULLET, of a rich carmine-red above and silvery white below; the other the STRIPED MULLET, or SUR-MULLET, which has a beautiful red colour on the back and sides, and from three to five bright yellow bands passing from head to tail. Till recently the striped form was regarded as the female of the plain red mullet, but many authorities incline to the view that the two are distinct species.

The SEA-BREAMS are fishes of the tropical and temperate regions, represented by a considerable number of species. Only one is at all abundant on the British coasts, and this occurs especially on the south and south-west coasts of England and Ireland. It is of an orange-scarlet colour above, and somewhat silvery on the sides, with a large black spot on the shoulder.

Several species of sea-bream occur in Australia, where they are known as SNAPPERS. One of the largest of these, which attains a length of more than 3 feet and a weight of over 40 lbs., is not only considered excellent eating, but is also the most popular sport-yielding fish of that colony.

The ancient Romans kept a species of sea-bream, the GILT-HEAD, in their vivariums, where it grew extremely fat. This species is said to stir up the sand with its tail, to discover buried shell-fish. It is particularly fond of mussels, and the noise it makes in crunching them between its jaws is loud enough to be heard by the fishermen.

Nearly allied to the Sea-breams are a group known, for want of a better name, as the THICK-RAYED FISHES, some of which rank as of prime importance among the food-fishes of the British Colonies. A general idea of the shape of the members of this family may be gathered from the photograph of an Australian GROPER. The name of LONG-FIN, given to one species, is bestowed on account of the fact that one or more of the rays of the breast-fin on each side is drawn out into a filament, often of very considerable length, which is used as an organ of touch. In other species, where the elongation is less, and more rays have undergone modification, an auxiliary organ of locomotion is the result. At the Cape of Good Hope species of long-fin are very abundant, and preserved in large quantities for export.

Other members of this family lack the elongated fin-rays altogether. The fishes known as the TUMPETERS of New Zealand and Tasmania belong to this section. They are considered by the colonists the best flavoured of any native fishes, and are eaten smoked as well as fresh. But two species are known, one ranging from 30 to 60 lbs. in weight, and the other, a much smaller form, scarcely attaining a weight of 20 lbs.; the latter is the more abundant of the two, though confined to the coast of New Zealand.

In the SCORPION-FISHES we have a small group including several forms remarkable for their ugliness, having added to an uncouth shape skinny appendages, which, projecting from the body, resemble rather leaves of seaweed than parts of the fish. These appendages, by their waving motion, serve either to attract other fishes or to afford concealment by their resemblance to the surrounding weeds. The ground-dwelling forms have some of the rays of the breast-fin modified into finger-like processes, like those of the Gurnards, by which they both crawl and feel. Some members of the family bear a rather close resemblance to the Sea-perches. In addition to their ugliness, some have become especially offensive by the transformation of certain of the fin-spines into poison-organs.

One of the ugliest, and at the same time most dreaded, of the family is the STONE-FISH figured on page 619. Each spine of the back fin is grooved. At the lower end of these grooves lies a pear-shaped bag containing a milky poison, which is conveyed to the point of the spine by ducts lying in the grooves. The native fishermen carefully avoid handling these fish; but persons walking with bare feet in the sea step upon the spines, and, receiving the poison into the wound, are killed.

All the scorpion-fish are carnivorous, and differ from the majority of fishes in that they produce their young alive. The smallest of the Spiny-finned fishes are members of this group, some scarcely exceeding 1½ inch in length. They are common amid the coral-reefs of the Pacific.

Passing over some comparatively unimportant members of this family, we come to a small group of vegetable-feeders from the Indo-Pacific, of which the TEUTHIS is one of the best known representatives. They are chiefly remarkable for the fact that the abdominal cavity is surrounded by a complete ring of bones, and that the air-bladder is forked at both ends. Some are rather brilliantly coloured.

The SLIME-HEADS, which constitute the next family, derive their name from the presence on the head of large mucus-bearing cavities covered with a thin skin. The eyes are always of great size, indicating a deep-sea habitat, or at least a depth only dimly lighted. All indeed, save two species, descend considerably below the surface, one species having been found in 345 fathoms. The species of one genus are believed to inhabit still greater depths, for their eyes are extremely small, indicating degeneration through disuse. The copious supply of slime is also an indication of a deep-sea habitat. The members of this family vary much in size and shape, but the most remarkable of all is a small and rare species found off Japan, in which the scales have joined together to form a perfectly solid armour, whilst the paired fins of the abdomen have been reduced to a single spine, with a few vestiges of other rays.

The next family, a comparatively small one, includes the TASSEL-FISH, so called from the long and delicate feelers springing from the base of the breast-fins, of which they originally formed a part. Varying in number from three to fourteen, these feelers can be moved independently of the fins. As these fishes all live in muddy water, and have the eyes obscured by films, such tactile organs are necessary, in order to enable them to procure their food. In some species they attain an enormous length. The flesh is highly esteemed. Some species have an air-bladder, which yields a good kind of isinglass, and forms an article of commerce in the East Indies. The majority are small species, but some attain to a length of 4 feet.

No less important than the preceding group, from an economic point of view, are the MEAGRES, a family of coast-haunting species of the tropical and sub-tropical Atlantic and Indian Oceans, exhibiting a special preference for the mouths of large rivers, into which they freely enter. Some, indeed, have become entirely fresh-water species.

One of the most interesting of the family is the species to which the name of DRUM has been given, from the extraordinary noise which it produces--though some other kinds emit similar noises. "These sounds," Dr. Günther writes, "can better be expressed by the word 'drumming' than any other. They appear to be very frequently heard by persons in vessels lying at anchor off the coasts of the United States, where these fishes are very common. The precise method by which these sounds are produced is not known. Since they are accompanied by a tremulous motion of the vessel, it seems more probable that they are due to the beating of the tails of the fish against the bottom of the ship to get rid of the parasites with which that part of their body is infested." The drum attains a length of more than 4 feet and a weight of over 100 lbs.

Though forming but a single small family, the SWORD-FISHES are nevertheless to be reckoned amongst the most interesting of living fishes. Attaining a length of from 12 to 15 feet, exceeding vigilant, pugnacious, and powerful, they are amongst the most formidable of all fishes. They derive their name from the great development of the upper jaw, which forms a huge, tapering, sword-like weapon, covered along its under-surface with numerous small teeth. They attack, apparently without provocation, whales and other large cetaceans, which they invariably succeed in killing by repeated thrusts of the sword. It appears that occasionally sword-fishes make a mistake, and, after the fashion of Don Quixote, tilt at windmills, in the shape of large vessels, under the impression that they are whales. But this most grave error of judgment brings with it a heavy penalty, in that, having no power to make effective backward movements, the sword remains fixed, and is eventually broken off in the struggle for freedom. Frank Buckland reminds us that in the Museum of the Royal College of Surgeons, London, is a section of the bow of a whaler impaled by one of these swords. That portion of the sword which remains is 1 foot long and 5 inches in circumference. "At one single blow," he writes, "the fish had plunged his sword through, and completely transfixed 13½ inches of solid timber. The sword had of course broken off and prevented a dangerous leak in the ship." In the British Museum is a second specimen of a ship's side in which the sword of a sword-fish is fixed.

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