Popular Science Monthly/Volume 28/January 1886/Fish Out of Water
By GRANT ALLEN.
STROLLING one day in what is euphemistically termed, in equatorial latitudes, "the cool of the evening," along a tangled tropical American field-path, through a low region of lagoons and water-courses, my attention happened to be momentarily attracted from the monotonous pursuit of the nimble mosquito by a small animal scuttling along irregularly before me, as if in a great hurry to get out of my way before I could turn him into an excellent specimen. At first sight I took the little hopper, in the gray dusk, for one of the common, small green lizards, and wasn't much disposed to pay it any distinguished share either of personal or scientific attention. But, as I walked on a little farther through the dense underbrush, more and more of these shuffling and scurrying little creatures kept crossing the path, hastily, all in one direction, and all, as it were, in a formed body or marching phalanx. Looking closer, to my great surprise I found they were actually fish out of water, going on a walking-tour, for change of air, to a new residence—genuine fish, a couple of inches long each, not eel-shaped or serpentine in outline, but closely resembling a red mullet in miniature, though much more beautifully and delicately colored, and with fins and tails of the most orthodox spiny and prickly description. They were traveling across-country in a bee-line, thousands of them together, not at all like the helpless fish out of water of popular imagination, but as unconcernedly and naturally as if they had been accustomed to the overland route for their whole life-times, and were walking now on the king's highway without let or hindrance.
I took one up in my hand and examined it more carefully; though the catching it wasn't by any means so easy as it sounds on paper, for these perambulatory fish are thoroughly inured to the dangers and difficulties of dry land, and can get out of your way when you try to capture them with a rapidity and dexterity which are truly surprising. The little creatures are very pretty, well-formed catfish, with bright, intelligent eyes, and a body armed all over, like the armadillo's, with a continuous coat of hard and horny mail. This coat is not formed of scales, as in most fish, but of toughened skin, as in crocodiles and alligators, arranged in two overlapping rows of imbricated shields, exactly like the round tiles so common on the roofs of Italian cottages. The fish walks, or rather shambles along ungracefully, by the shuffling movement of a pair of stiff spines placed close behind his head, aided by the steering action of his tail, and a constant snake-like wriggling motion of his entire body. Leg-spines of somewhat the same sort are found in the common English gurnard, and, in this ago of aquariums ami fisheries exhibitions, most adult persons above the age of twenty-one years must have observed the gurnards themselves crawling along suspiciously by their aid at the bottom of a tank at the Crystal Palace or the polyonymous South Kensington building. But, while the European gurnard only uses his substitutes for legs on the bed of the ocean, my itinerant tropical acquaintance (his name, I regret to say, is Callichthys) uses them boldly for terrestrial locomotion across the dry lowlands of his native country. And, while the gurnard has no less than six of these pro-legs, the American land-fish has only a single pair with which to accomplish his arduous journeys. If this be considered as a point of inferiority in the armor-plated American species, we must remember that while beetles and grasshoppers have as many as six legs apiece, man, the head and crown of things, is content to scramble through life ungracefully with no more than two.
There are a great many tropical American pond-fish which share these adventurous gypsy habits of the pretty little Callichthys. Though they belong to two distinct groups, otherwise unconnected, the circumstances of the country they inhabit have induced in both families this queer fashion of waddling out courageously on dry land, and going on voyages of exploration in search of fresh ponds and shallows new, somewhere in the neighborhood of their late residence. One kind in particular, the Brazilian Doras, takes land-journeys of such surprising length that he often spends several nights on the way, and the Indians who meet the wandering bands during their migrations fill several baskets full of the prey thus dropped upon them, as it were, from the kindly clouds.
Both Doras and Callichthys, too, are well provided with means of defense against the enemies they may chance to meet during their terrestrial excursions; for in both kinds there are the same bony shields along the sides, securing the little travelers, as far as possible, from attack on the part of hungry piscivorous animals. Doras further utilizes its powers of living out of water by going ashore to fetch dry leaves, with which it builds itself a regular nest, like a bird's, at the beginning of the rainy season. In this nest the affectionate parents carefully cover up their eggs, the hope of the race, and watch over them with the utmost attention. Many other fish build nests in the water, of materials naturally found at the bottom; but Doras, I believe, is the only one that builds them on the beach, of materials sought for on the dry land.
Such amphibious habits on the part of certain tropical fish are easy enough to explain by the fashionable clew of "adaptation to environment." Ponds arc always very likely to dry up, and so the animals that frequent ponds are usually capable of bearing a very long deprivation of water. Indeed, our evolutionists generally hold that land animals have in every case sprung from pond-animals which have gradually adapted themselves to do without water altogether. Life, according to this theory, began in the ocean, spread up the estuaries into the greater rivers, thence extended to the brooks and lakes, and finally migrated to the ponds, puddles, swamps, and marshes, whence it took at last, by tentative degrees, to the solid shore, the plains, and the mountains. Certainly the tenacity of life shown by pond-animals is very remarkable. Our own English carp bury themselves deeply in the mud in winter, and there remain in a dormant condition many months entirely without food. During this long hibernating period, they can be preserved alive for a considerable time out of water, especially if their gills are, from time to time, slightly moistened. They may then be sent to any address by parcels-post, packed in wet moss, without serious damage to their constitution; though, according to Dr. Günther, these dissipated products of civilization prefer to have a piece of bread steeped in brandy put into their mouths to sustain them beforehand. In Holland, where the carp are not so sophisticated, they are often kept the whole winter through, hung up in a net to keep them from freezing. At first they require to be slightly wetted from time to time, just to acclimatize them gradually to so dry an existence; but after a while they adapt themselves cheerfully to their altered circumstances, and feed on an occasional frugal meal of bread and milk with Christian resignation.
Of all land-frequenting fish, however, by far the most famous is the so-called climbing-perch of India, which not only walks bodily out of the water, but even climbs trees by means of special spines, near the head and tail, so arranged as to stick into the bark and enable it to wriggle its way up awkwardly, something after the same fashion as the "looping" of caterpillars. The tree-climber is a small, scaly fish, seldom more than seven inches long; but it has developed a special breathing apparatus to enable it to keep up the stock of oxygen on its terrestrial excursions, which may be regarded as to some extent the exact converse of the means employed by divers to supply themselves with air under water. Just above the gills, which form of course its natural hereditary breathing apparatus, the climbing-perch has invented a new and wholly original water-chamber, containing within it a frilled bony organ, which enables it to extract oxygen from the stored-up water during the course of its aerial peregrinations. While on shore it picks up small insects, worms, and grubs; but it also has vegetarian tastes of its own, and does not despise fruits and berries. The Indian jugglers tame the climbing-perches and carry them about with them as part of their stock in trade; their ability to live for a longtime out of water makes them useful confederates in many small tricks which seem very wonderful to people accustomed to believe that fish (lie almost at once when taken out of their native element.
The Indian snakehead is a closely allied species, common in the shallow ponds and fresh-water tanks of India, where holy Brahmans bathe and drink and die and are buried, and most of which dry up entirely during the dry season. The snakehead, therefore, has similarly accommodated himself to this annual peculiarity in his local habitation by acquiring a special chamber for retaining water to moisten his gills throughout his long deprivation of that prime necessary, lie lives composedly in semi-fluid mud, or lies torpid in the hard-baked clay at the bottom of the dry tank from which all the water has utterly evaporated in the drought of summer. As long as the mud remains soft enough to allow the fish to rise slowly through it, they come to the surface every now and then to take in a good hearty gulp of air, exactly as gold-fish do in England when confined with thoughtless or ignorant cruelty in a glass globe too small to provide sufficient oxygen for their respiration. But when the mud hardens entirely they hibernate, or rather æstivate, in a dormant condition until the bursting of the monsoon fills the ponds once more with the welcome water. Even in the perfectly dry state, however, they probably manage to get a little air every now and again through the numerous chinks and fissures in the sun-baked mud. Our Aryan brother then goes a-fishing playfully with a spade and bucket, and digs the snakehead in this mean fashion out of his comfortable lair with an ultimate view to the manufacture of pillau. In Bunnah, indeed, while the mud is still soft the ingenious Burmese catch the helpless creatures by a still meaner and more unsportsmanlike device. They spread a large cloth over the slimy ooze where the snakeheads lie buried, and so cut off entirely for the moment their supply of oxygen. The poor fish, half-asphyxiated by this unkind treatment, come up gasping to the surface under the cloth in search of fresh air, and are then easily caught with the hand and tossed into baskets by the degenerate Buddhists.
Old Anglo-Indians even say that some of these mud-haunting Oriental fish will survive for many years in a state of suspended animation, and that, when ponds or jhils which are known to have been dry for several successive seasons are suddenly filled by heavy rains, they are found to be swarming at once with full-grown snakeheads, released in a moment from what I may venture to call their living tomb in the hardened bottom. Whether such statements are absolutely true or not the present deponent would be loath to decide dogmatically; but, if we were implicitly to swallow everything that the old Anglo-Indian in his simplicity assures us he has seen—well, the clergy would have no further cause any longer to deplore the growing skepticism and unbelief of these latter unfaithful ages. This habit of lying in the mud and there becoming torpid may be looked upon as a natural alternative to the habit of migrating across country, when your pond dries up, in search of larger and more permanent sheets of water. Some fish solve the problem how to get through the dry season in one of these two alternative fashions, and some in the other. In flat countries where small ponds and tanks alone exist, the burying plan is almost universal; in plains traversed by largo rivers or containing considerable scattered lakes, the migratory system finds greater favor with the piscine population.
One tropical species which adopts the tactics of hiding itself in the hard clay, the African mud-fish, is specially interesting to us human beings on two accounts: first, because, unlike almost all other kinds of fish, it possesses lungs as well as gills; and, secondly, because it forms an intermediate link between the true fish and the frogs or amphibians, and therefore stands in all probability in the direct line of human descent, being the living representative of one among our own remote and early ancestors. Scientific interest and filial piety ought alike to secure our attention for the African mud-fish. It lives its amphibious life among the rice-fields on the Nile, the Zambesi, and the Gambia, and is so greatly given to a terrestrial existence that its swim-bladder has become porous and cellular, so as to be modified into a pair of true and serviceable lungs. In fact, the lungs themselves in all the higher animals are merely the swim-bladders of fish, slightly altered so as to perform a new but closely allied office. The mud-fish is common enough in all the larger English aquariums, owing to a convenient habit in which it indulges, and which permits it to be readily conveyed to all parts of the globe on the same principle as the vans for furniture. When the dry season comes on and the rice-fields are reduced to banks of baking mud, the mud-fish retire to the bottom of their pools, where they form for themselves a sort of cocoon of hardened clay, lined with mucus, and with a hole at each end to admit the air; and in this snug retreat they remain torpid till the return of wet weather. As the fish usually reach a length of three or four feet, the cocoons are of course by no means easy to transport entire. Nevertheless, the natives manage to dig them up whole, fish and all; and, if the capsules are not broken, the unconscious inmates can be sent across by steamer to Europe with perfect safety. Their astonishment when they finally wake up after their long slumber, and find themselves inspecting the British public, as introduced to them by Mr. Farini, through a sheet of plate-glass, must be profound and interesting.
In England itself, on the other hand, we have at least one kind of fish which exemplifies the opposite or migratory solution of the dry pond problem, and that is our familiar friend the common eel. The ways of eels are indeed mysterious, for nobody has ever yet succeeded in discovering where, when, or how they manage to spawn; nobody has ever yet seen an eel's egg, or caught a female eel in the spawning condition, or even observed a really adult male or female specimen of perfect development. All the eels ever found in fresh water are immature and undeveloped creatures. But eels do certainly spawn somewhere or other in the deep sea, and every year, in the course of the summer, flocks of young ones, known as elvers, ascend the rivers in enormous quantities, like a vast army under numberless leaders. At each tributary or affluent, be it river, brook, stream, or ditch, a proportionate detachment of the main body is given off to explore the various branches, while the central force wriggles its way up the chief channel, regardless of obstacles, with undiminished vigor. When the young elvers come to a weir, a wall, a flood-gate, or a lasher, they simply squirm their way up the perpendicular barrier with indescribable wrigglings, as if they were wholly unacquainted, physically as well as mentally, with Newton's magnificent discovery of gravitation. Nothing stops them; they go wherever water is to be found; and, though millions perish hopelessly in the attempt, millions more survive in the end to attain their goal in the upper reaches. They even seem to scent ponds or lakes mysteriously, at a distance, and will strike boldly straight across-country, to sheets of water wholly cut off from communication with the river which forms their chief highway.
The full-grown eels arc also given to journeying across-country in a more sober, sedate, and dignified manner, as becomes fish which have fully arrived at years, or rather months, of discretion. When the ponds in which they live dry up in summer, they make in a bee-line for the nearest sheet of fresh water, whose direction and distance they appear to know intuitively, through some strange instinctive geographical faculty. On their way across-country they do not despise the succulent rat, whom they swallow whole, when caught, with great gusto. To keep their gills wet during these excursions, eels have the power of distending the skin on each side of the neck, just below the head, so as to form a big pouch or swelling. This pouch they fill with water, to carry a good supply along with them until they reach the ponds for which they are making. It is the pouch alone that enables eels to live so long out of water under all circumstances, and so incidentally exposes them to the disagreeable experience of getting skinned alive, which, it is to be feared, still forms the fate of most of those that fall into the clutches of the human species.
A far more singular walking fish than any of these is the odd creature that rejoices (unfortunately) in the very classical surname of Periophthalmus, which is, being interpreted, Stare-about. (If ho had a recognized English name of his own, I would gladly give it; but, as he hasn't, and as it is clearly necessary to call him something, I fear we must stick to the somewhat alarming scientific nomenclature.) Periophthalmus, then, is an odd fish of the tropical Pacific shores, with a pair of very distinct fore-legs (theoretically described as modified pectoral fins), and with two goggle-eyes, which he can protrude at pleasure right outside the sockets, so as to look in whatever direction he chooses, without even taking the trouble to turn his head to left or right, backward or forward. At ebb-tide this singular peripatetic goby literally walks straight out of the water, and promenades the bare beach erect on two legs in search of small crabs and other stray marine animals left behind by the receding waters. If you try to catch him, he hops away briskly much like a frog, and stares back at you grimly over his left shoulder with his squinting optics. So completely adapted is he for this amphibious longshore existence that his big eyes, unlike those of most other fish, are formed for seeing in the air as well as in the water. Nothing can be more ludicrous than to watch him suddenly thrusting these very movable orbs right out of their sockets like a pair of telescopes, and twisting them round in all directions so as to see in front, behind, on top, and below, in one delightful circular sweep.
There is also a certain curious tropical American carp, which, though it hardly deserves to be considered in the strictest sense as a fish out of water, yet manages to fall nearly half-way under that peculiar category, for it always swims with its head partly above the surface and partly below. But the funniest thing in this queer arrangement is the fact that one half of each eye is out in the air and the other half is beneath in the water. Accordingly, the eye is divided horizontally by a dark strip into two distinct and unlike portions, the upper one of which has a pupil adapted to vision in the air alone, while the lower is adapted to seeing in the water only. The fish, in fact, always swims with its eye half out of the water, and it can see as well on dry land as in its native ocean. Its name is Anableps, but, in all probability, it does not wish the fact to be generally known.
The flying-fish are fish out of water in a somewhat different and more transitory sense. Their aërial excursions are brief and rapid; they can only fly a very little way, and have soon to take once more for safety to their own more natural and permanent element. More than forty kinds of the family are known, in appearance very much like English herrings, but with the front fins expanded and modified into veritable wings. It is fashionable nowadays among naturalists to assert that the flying-fish don't fly; that they merely jump horizontally out of the water with a powerful impulse, and fall again as soon as the force of the first impetus is entirely spent. When men endeavor to persuade you to such folly, believe them not. For my own part, I have seen the flying-fish fly—deliberately fly, and flutter, and rise again, and change the direction of their flight in mid-air, exactly after the fashion of a big dragon-fly. If the other people who have watched them haven't succeeded in seeing them fly, that is their own fault, or, at least, their own misfortune; perhaps their eyes weren't quick enough to catch the rapid, though to me perfectly recognizable, hovering and fluttering of the gauze-like wings; but I have seen them myself, and I maintain that on such a question one piece of positive evidence is a great deal better than a hundred negative. The testimony of all the witnesses who didn't see the murder committed is as nothing compared with the single testimony of the one man who really did see it. And in this case I have met with many other quick observers who fully agreed with me against the weight of scientific opinion, that they have seen the flying-fish really fly with their own eyes, and no mistake about it. The German professors, indeed, all think otherwise; but then the German professors all wear green spectacles, which are the outward and visible sign of "blinded eyesight poring over miserable books." The unsophisticated vision of the noble British seaman is unanimously with me on the matter of the reality of the fishes' flight.
Another group of very interesting fish out of water are the flying gurnards, common enough in the Mediterranean and the tropical Atlantic. They are much heavier and bigger creatures than the true flying-fish of the herring type, being often a foot and a half long, and their wings are much larger in proportion, though not, I think, really 60 powerful as those of their pretty little silvery rivals. All flying-fish fly only of necessity, not from choice. They leave the water when pursued by their enemies, or when frightened by the rapid approach of a big steamer. So swiftly do they fly, however, that they can far outstrip a ship going at the rate of ten knots an hour; and I have often watched one keep ahead of a great Pacific liner under full steam for many minutes together in quick, successive flights of three or four hundred feet each. Oddly enough, they can fly farther against the wind than before it—a fact acknowledged even by the spectacled Germans themselves, and very hard indeed to reconcile with the orthodox belief that they are not flying at all, but only jumping. I don't know whether the flying gurnards are good eating or not; but the silvery flying-fish are caught for market (sad desecration of the poetry of Nature!) in the Windward Islands, and, when nicely fried in egg and bread-crumb, are really quite as good, for practical purposes, as smelts or whiting, or any other prosaic European substitute.
On the whole, it will be clear, I think, to the impartial reader, from this rapid survey, that the helplessness and awkwardness of a fish out of water have been much exaggerated by the thoughtless generalization of unscientific humanity. Granting, for argument's sake, that most fish prefer the water, as a matter of abstract predilection, to the dry land, it must be admitted per contra that many fish cut a much better figure on terra firma than most of their critics themselves would cut in mid-ocean. There are fish that wriggle across country intrepidly with the dexterity and agility of the most accomplished snakes; there are fish that walk about on open sand-banks, semi-erect on two legs, as easily as lizards; there are fish that hop and skip on tail and fins in a manner that the celebrated jumping-frog himself might have observed with envy; and there are fish that fly through the air of heaven with a grace and swiftness that would put to shame innumerable species among their feathered competitors. Nay, there are even fish, like some kinds of eels and the African mud-fish, that scarcely live in the water at all, but merely frequent wet and marshy places, where they lie snugly in the soft ooze and damp earth that line the bottom. If I have only succeeded, therefore, in relieving the mind of one sensitive and retiring fish from the absurd obloquy cast upon its appearance when it ventures away for a while from its proper element, then, in the pathetic and prophetic words borrowed from a thousand uncut prefaces, this work will not, I trust, have been written in vain.—Cornhill Magazine.