Popular Science Monthly/Volume 12/January 1878/The Archer-Fishes
|←Illustrations of the Logic of Science II||Popular Science Monthly Volume 12 January 1878 (1878)
By Henri Émile Sauvage
IN the elegance and variety of their colors, in the splendor and brilliancy of the tints with which they have been adorned by Nature, marine animals have no reason to envy the inhabitants of air; and if in the tropical regions of Africa and America the forests are embellished by the presence of innumerable birds of gorgeous plumage, the Indian Ocean and the Antilles Sea possess countless lesions of fishes that are more beautiful still, whose scales flash with all the colors of the metals and precious stones, while a thousand varied ornamentations are traced in vivid colors on the general tone.
The animals known to our colonists on the Antilles Islands under the names of Demoiselles, Portugais, Bandoulières, are, in this respect, not inferior to the most richly-adorned of fishes. Accustomed to keep near the shore, amid the rocks and in shallow waters, swimming swiftly and ever moving, they are constantly reflecting the splendid colors with which they are decorated. Rose-color, purple, azure, velvety-black, milk-white, are gorgeously displayed on their surface, in the form of bands, streaks, curved lines running in various directions, rings, ocellated spots. These colors stand out boldly on the surface of the body, which furnishes a background of the richest nacreous tints of gold and silver, or of polished steel.
In all of these fishes the body is compressed, and the vertical fins are covered with scales, whence the name Squamipinnes, by which they are known to naturalists. The shape of the body is sometimes peculiar, and the buffalo or cow fish of the Malays is one of the most curious of the class, as well by reason of the protuberance and the sharp, recurved horns of the head, and the compressed and unequal spines of the back, as on account of the broad, yellow, green, and brown zebraizations which adorn the body. The jaws sometimes are armed with minute teeth like the nap of velvet, as in the archer-fish; sometimes these teeth are superseded by fine, compact, silky filaments, performing the same functions as the barbs of the whale—they serve to strain the water and to retain the little animals on which the fish preys. The fishes of this class are the Chœtodon, with its rich colors; the Holacanthus, which is perhaps the most beautiful member of the family; the Pomacanthus, known to our French colonists as Le Portugais (the Portuguese); and sundry others.
Of the Chœtodons, some have the muzzle long and slender, formed by the bones of the jaw, which are united along nearly their entire length by a membrane, so that the mouth is simply an horizontal slit at the extremity of this cylinder, or elongated cone. The vertical diameter of the body is very great, and the upright fin of the back is high and scaly; the tail is cut square; the profile, which is concave in front of the eyes, rises almost vertically, so that the snout is about one-fourth the depth of the head. These fishes, known under the name of Chelmons, inhabit the Indian Ocean; naturalists distinguish two species, the beaked Chelmon and the long-beaked Chelmon (see the latter in Fig. 1). These species differ from each other not only in length of beak, but also in the arrangement of the colors which adorn them.
In the beaked Chelmon the body is greenish and iridescent; the fins are green, with reflection of azure; a black spot, surrounded by a pearl-white circle, is seen on the dorsal fin, in length about one-third that of the soft rays; five vertical stripes of azure-color, and bordered with a nacreous white line, adorn the body; one of these stripes crosses the eye obliquely; a second one, bisecting the nape of the neck, extends to the ventral fins; the next two mark the flanks, and the posterior stripe bisects the root of the caudal fin.
The long-beaked Chelmon's body is yellow. Instead of the stripe crossing the eye, seen in the other species, we find on the anterior portion of the body a broad, blackish spot, triangular in shape, and terminating in a point on the snout. This spot is bordered by a nacreous white stripe; the forehead is of azure tint, with a shade of sea-green; the eye is of a pure rose-color; a narrow stripe of black adorns the margin of the fins, which themselves are of mauve-color; on the posterior part of the anal fin, near its edge, is seen a deep-black spot, encircled by a line of pearly white.
The Chelmon, particularly the beaked Chelmon, has been described by Schlosser, under the title of Archer-fish, in the "Philosophical Transactions." The animal is said to obtain its food in a peculiar way, and hence the names given to it by Schlosser (Jaculator) and by the Dutch colonists of the East Indies (Spuytvisch, pump-fish or spitting-fish).
Lacépède, following the narratives of travelers, tells us that the long-beaked Chœcetodon "usually keeps near to the mouths of rivers, and especially frequents places where the water is not deep. It feeds on insects, especially such as live on the marine plants which rise above the surface of the sea. In taking them it resorts to a noteworthy manœuvre, which it is enabled to perform by the very elongated form of the snout; and a similar sort of manœuvre is performed by the Sparus insidator, the bellows-chœtodon, and other fishes, with very long, very narrow, and nearly cylindrical beak, like that of the animal we are now describing. When the archer espies an insect which it wishes to seize, but which is flying too high above the surface to be captured by leaping out of the water, it approaches as near as possible to its prey, then it fills its mouth-cavity with water, shuts its gill-openings, suddenly compresses its little slit of a mouth, and, ejecting rapidly the water through the very narrow tube which forms its snout, squirts it often to the distance of two metres, and that with such force that the insect is stunned and falls into the sea. The performance is so amusing that rich people throughout the greater part of the East Indies keep long-beaked Chœtodons in large vessels."
Block, in his "History of Fishes," which was published at the close of the last century, tells us, on the authority of Mynheer Hommel, inspector of the Batavia Hospital, that the bandoulière or beaked Chœtodonshas a very singular way of procuring food. "Observe," says Bloch, "how this fish ensnares the flies it discovers on the marine plants which project above the water. It approaches within four to six feet of the insect, and then squirts water upon it with such force that it never fails to bring it down and make it its prey." Mynheer Hommel himself made the following experiment: He had a few of these fishes placed in a large vessel containing sea-water. When they had become accustomed to this prison, lie ran a pin through a fly, and made it fast to one side of the vessel. He then was so fortunate as to see "these fishes vying with one another in their efforts to seize the fly, and continually squirting little drops of water, without ever missing their aim."
We owe it to truth to add that Bleeker, who resided so long in the Dutch Indies, and who is perfectly familiar with the ichthyological fauna of that region, not only finds in the habits of the bandoulière no confirmation of this singular method of catching insects, but he never even heard it mentioned during his sojourn at Batavia. "Certain it is," adds he, "that at Batavia this species inhabits only the waters of the reefs of the little islands in the bay, and never visits the swampy and sandy beach in the vicinity of the capital, or the mouths of the rivers."
A fish belonging to the same family—Squamipinnes—but classed in another group, has likewise received from Schlosser and Pallas the name of Archer.
Four species, inhabiting the waters of Polynesia and the Indian Archipelago, constitute this group of the Archers, or Toxotæ. Instead of being more or less oval in shape, as is the case with the Chœtodons, the body is here elongated, the line of the back being nearly straight, while that of the belly is curved, so that the fish assumes a triangular
shape. The distinguishing feature of these fishes is the backward position of the dorsal fin, which, relegated to the posterior part of the body, is armed with only three or four spines (Fig. 2). The head, lying in the same plane with the line of the back, is pointed; the eye is large, and the mouth opens wide. The brilliant colors of the Chœtodons, properly so called, are here wanting; the body is olive-brown or yellow, and bears broad, round, or oblong spots, or vertical stripes of black color; the eye is rose-color and brilliant; the belly, silvery-white.
According to Cuvier and Valencienne, "though the mouth of this fish differs immensely in its organization from that of Chelmon, it, too, can shoot drops of water to a great height, and can hit, with almost unerring aim, insects and other little animals on aquatic plants, or even on the herbage at the water's edge. The inhabitants of sundry regions in India," add these authors, "and particularly the Chinese in Java, keep these fish in their houses for the sake of the amusement afforded by witnessing their performances, offering it ants, and flies on a string, or on the end of a stick, brought within range. . . . The species is known in the Indian Archipelago under the Malay name of ikcansumpit."
Bleeker, in a recent work on the Toxotæ, tells us that at Batavia this fish is no longer kept, as it appears to have been a century ago, either by Europeans or by the Chinese. He further says that neither from Chinese nor from natives, whether at Batavia or elsewhere, has he been able to obtain any confirmation of the accounts which have been given concerning its skill in seizing its prey. According to him, the celebrity enjoyed by the archer-fish is undeserved, and rests upon a misapprehension; in short, he shows from the very texts of Pallas and Schlosser that Hommel's observation applies to the long-beaked Chelmon, of which we have spoken above, and that like habits have been gratuitously attributed to the two species, they having been regarded as generically identical.—La Nature.
- Translated from the French, by J. Fitzgerald, A.M.