Aquatic

“ THE VEGETATION OF THE MARINE AQUARIUM. As the forest must be planted before its denizens can luxuriate in its shades, so the submarine shrubbery of the Aquarium must be perfected before the aquatic animals can be introduced. For it has been shown, in tracing the history of the experiments which resulted in the establishment of the principles that regulate the formation of Aquaria, that it is by plants only that a supply of oxygen can be kept up, sufficient for the health and existence of all forms of animal life beneath the water. ”

“ Distribution of Water in Aquaria.—In constructing aquaria it is important to bear in mind the fact that, for aquatic animals which breathe without lungs, the value of water does not depend so much on its amount, as upon its distribution in such a manner that it may be sufficiently oxygenated by contact with the atmosphere. ”

“ In addition to the fins, an aquatic animal is furnished with an air bladder, a philosophical apparatus in its body; this sustains and enables it, at will to raise itself to the surface of the water, or, otherwise, to descend. When any accident has burst this air bladder, or it has been punctured by way of experiment, the fish remains at the bottom of the vessel or river, totally unable to ascend. ”

“ Aquatic in different ways, the differences depending on bodily relation to external temperature and on habit of life, are such animals on the one hand as take in air but live in water, and such on the other hand as take in water and are furnished with gills but go upon dry land and get their living there. ”

“ That is to say, aquatic forms which are in one place annually subject to a slight want of water for a short time, are elsewhere subject to greater wants for longer times: we have gradations of transition, analogous to those which the tides furnish. ”

“ Divers can remain some time; but the birds that remain the longest under water are the semi-aquatic, whose feet are only half-webbed. I have watched the common English water-hen for many minutes walking along at the bottom of a stream, apparently as much in its element as if on shore, pecking and feeding as it walked. ”

“ It is to be found only in clear mountain lakes, for it is a true aquatic alpine, frequent only in the North of England, and in Scotland and Ireland. The aquarian who resides near any mountain lake or pool, should seek for it, and treasure it as the choicest gem in his collection. ”

“ On the shores of one of these pools, of size not so great that the waves may attain a considerable height, or in the sheltered bay of a larger lake, various aquatic plants, especially the species of pond lilies, take root upon the bottom, and spread their expanded leaves on the surface of the water. These flexible-leaved and elastic-stemmed plants can endure waves which attain no more than a foot or two of height, and by the friction which they afford make the swash on the shore very slight. ”

“ A Animal life had its beginning in the waters, and to this day the waters are the chief habitat of animals, especially of the lower forms. If we divide the animal kingdom into great leading types, the lowest of these groups, the Protozoa, includes only aquatic forms; the next, that of the coral animals and their allies, is also aquatic. So are all the species of the Sea Urchins and Star Fishes. Of the remaining groups, the Mollusks, the Crustaceans, and the Worms are dominantly aquatic, only a small proportion being air-breathers. ”

“ Aquatic mammals which pass their lives entirely, or, for the greater part, in the water are, of course, subject to very different laws of distribution from those of the terrestrial forms. As regards aquatic mammals, land is of course an impassable barrier to their extension, and, subject to restrictions in certain cases, water offers them a free passage. ”

“ Aqua ́rium, a vessel or series of vessels constructed wholly or partly of glass and containing salt or fresh water in which are kept living specimens of marine or fresh-water animals along with aquatic plants. In principle the aquarium is based on the interdependence of animal and vegetable life; animals consuming oxygen and exhaling carbonic acid, plants reversing the process by absorbing carbonic acid and giving out oxygen. The aquarium must consequently be stocked both with plants and animals, and for the welfare of both something like a proper proportion should exist between them. ”

“ For aquatic animals, water is their medium; without it they die. However the condition of the water is also important: dissolved salts and oxygen, currents and levels of light may be critical. Aquatic animals evolve to suit specific hydrological conditions: if these conditions change the animals may die. ”

“ By far the greater part of the animals whose remains are found in the older strata are aquatic, and the vast extents over which they are distributed, show, that the waters must at one time have covered a very great proportion of what is now dry land. ”

“ The aquatic animal becomes through several transitions a land-animal, and then the land-animal through other transitions becomes now an aërial animal like the bat and now an aquatic animal like the whale. ”

“ The stream of water also passes but once along the gills of fish, as it is sooner deprived of its virtue; whereas the air is both received and ejected by the action of the lungs of land-animals. The whale seems to be an exception to the above, as he receives water and spouts it out again from an organ, which I suppose to be a respiratory one. As spring-water is nearly of the same degree of heat in all climates, the aquatic plants, which grow in rills or fountains, are found equally in the torrid, temperate, and frigid zones, as water-cress, water-parsnip, ranunculus, and many others. ”

“ And ’tis very plain, that if one Acre was twice as rich as the other, it must be able to nourish Five Quarters better than the other could nourish Three Quarters.
Air is necessary to the Life and Health of all Plants, tho’ in very different Degrees: Aquatics, which live under Water, are content with as little Air, as their Companions the Fishes. ”

“ INSECTIVORA, an order of non-volant placental mammals of small size, with a dentition adapted to an insect-diet. In nearly all cases these creatures are nocturnal, and the majority are terrestrial, many burrowing in the ground, although a few are arboreal and others aquatic. They have plantigrade or partially plantigrade feet, that is to say, they apply the whole or the greater portion of the soles to the ground when walking; and there are generally five toes, each terminating in a claw, and the first never being opposable to the others in either the fore or hind limb. ”

“ They swim about in companies of some hundreds, and frequent the still water of deep pools, will not take a bait, and are only seen when the water is clear. Then it is a delightful sight for any one to lie upon the bank of some ti-tree-fringed creek or pool, when the sun illumines the water and reveals the bottom, and watch a school of these fish swimming closely and very slowly together, passing over submerged logs, roots of trees or rocks, their scales of pure silver gleaming in the sunlight as they make a simultaneous side movement. ”

“ If, spite of everything, the seawater fail, then try a fresh-water aquarium. Use your tank for the pond instead of the ocean; and in the spotted newt, the tortoise, the tadpole, the caddis-worm, and the thousand other inhabitants of our inland ponds and brooks, with the weeds among which they live, you will find as much entertainment as in watching the wonders of the great sea. ”

“ A prawn or two, and a few minute star-fish, will make your aquarium complete; though you may add to it endlessly, as one glance at the salt-water tanks of the Zoological Gardens, and the strange and beautiful forms which they contain, will prove to you sufficiently.
You have two more enemies to guard against, dust, and heat. If the surface of the water becomes clogged with dust, the communication between it and the life-giving oxygen of the air is cut off ”

“ In this small space may be found animal and vegetable life of all kinds, anemonæ, lovely weeds, zoophytes, curious fish, sponges, shells, coral, and a hundred other things, all in such perfection and orderly wildness that no artificial aquarium [Pg 153] can ever hope to present, for they are made by hands, and can never vie with Nature in the formation of the wild and picturesque aspect of these rocky pools. ”

“ The bottom of the aquarium should be covered with a layer of sand from one to two inches thick, upon the top of which should be placed a few pebbles, in patches. For marine aquaria, the sand must be procured from the sea-beach, or a river-side, below the tide-mark, and, for those of fresh water, from the bed of a brook or running stream, and, in either case, it must be thoroughly washed, to free it from impurities. Rock-work may be built upon the sand, to form caves and grottoes, but there should not be any hiding-places for impurities to collect in. ”

“ Spring water will do very well, but must stand a day or two to allow the plants to soften it, before the fishes are put in. My tanks are all filled with spring water, which I find altogether unobjectionable; but for the marine tank I think it preferable to any other in the manufacture of artificial sea-water. Writers on the aquarium usually insist on the use of river water, but in many places this is not attainable, and it is satisfactory to know that artesian, or well water, will serve the purpose admirably. ”

“ The marine aquarium must be supplied with sea-water taken not less than a mile from shore, or from the middle of a large river. When any is lost from the tank by evaporation, add fresh rain-water to supply the deficiency ”

“ The fresh-water forms are specifically distinct from those incidental to salt or brackish water,—fresh-water species, however, are sometimes carried some distance into the sea by the force of the current, and in tidal rivers marine forms are carried up by the force of the tide. ”

“ Artificial water soon acquires the properties of natural sea water under the influence of these plants, which grow rapidly, and disseminate their spores throughout the tank, at the same time giving abundance of oxygen for the support of animal life. ”

“ When many gold-fish are kept in a small aquarium, as with thoughtless cruelty they frequently are, they swim close to the surface, so as to breathe that water which is from instant to instant absorbing fresh oxygen. ”

“ But for anemones of all kinds, many mollusks and crustaceans, and some other forms to be presently described, artificial water does well, and improves daily if properly managed. Unless, therefore, the aquarian is bent upon domesticating the rarer and more delicate sea specimens, he may avail himself of the aid of the chemist, and manufacture sea-water from the river or the pump. ”

“ The cut at the head of this chapter, of an aquarium, represents a new appliance of modern times, which is a most valuable aid in our obtaining a knowledge of the habits of the animals living in the sea. In fresh water, as well as in salt, the mutual relations of the vegetable and animal life serve to keep the water from becoming stagnant. The plants secrete the carbonic acid gas, which the animals give to the water by breathing, and in so doing free the oxygen which the animals require. ”

“ After various transformations and subdivisions these bodies develop into the wonderfully beautiful and fairy-like jelly-fish which you find swimming in the deep waters of the bay, some of them trailing long, filmy, lace-like skirts or veils as they move.
The delicate red, green, yellow, pink, and lavender blossoms, which add so much to the beauty of the pool, are
Sea-anemones Animals, too, every one, living only on animal food, which they find and absorb in a peculiar manner. ”

“ I have had an opportunity elsewhere of observing a curious change which fresh water induces in this fish. In the brackish water of an estuary, the animal becomes, without diminishing in general size, thicker and more fleshy than when in its legitimate habitat, the sea: but the flesh loses in quality what it gains in quantity;—it grows flabby and insipid, and the margin-fin lacks always its strip of transparent fat. ”

“ The alternate rising and falling of the water produced in the manner just described represents in miniature the flow and ebb of the tides, but perhaps this is in itself of no great advantage in the aquarium except from the fact that it allows those creatures that prefer to be occasionally out of the water for a time a better opportunity of indulging in such a habit. ”

“ THE FISH AND CRUSTACEANS OF THE AQUARIUM. A marine Aquarium may be rendered very interesting without the introduction of fish, and as their presence requires that the water should be once each day aerated by means of additional water, introduced by the syringe or by a drip, continuing for some time from another vessel, many may prefer the lovely Sea-Weeds, curious Zoöphytes, and beautiful Molluscs, alone ”

“ These animalcules living never in thermal water, they are only to be seen at a few inches distance from the wells, and when kept in glasses or pots, they soon retreat towards the sides of the vessel. They are never found in the limpid water of a cold spring, river or well, nor of a hot spring, even if the water has reposed for hours and days, so that we can consider as erroneous, and suggested by a fondness for marvellous things, the popular opinion, so generally spread, that we swallow with common water innumerable animalcules. ”

“ The aquarium must be ventilated. Its top should be broad and open. Every little fish, snail and insect wants air, just as every boy and girl wants it. A certain quantity of air is mixed with the water, and the creatures must breathe that or come to the surface for their supply. How does Mother Nature manage the ventilation of her aquaria,—the ponds and streams? The plants furnish part of the air, as we have said. The open pond, whose surface is ruffled by every passing breeze, is constantly being provided with fresh air. ”