The American Boy's Handy Book/Chapter 7
The first introduction of the aquarium revealed another world and its inhabitants: a world of enchantment, far surpassing any described in the "Arabian Nights" or fairy tales; a world teeming with life so strange that some of it we can scarcely believe to be real.
The marine aquarium has laid bare secrets that have been locked in the breast of the ocean for ages. Through the crystal sides of the tanks are now shown living animals, of forms so lovely and delicate as to remind us of the tracery of frost-work. We can behold in the transparent waters fishes circling about, with distended fins that resemble the gorgeous wings of butterflies; and we can see, glancing here and there, other fish, the glitter of whose glossy sides dazzles us and is as various in hue as the rainbow. The rocks at the bottom are carpeted with animals in the forms of lovely flowers!
The remarks in regard to the form and general construction of fresh-water aquariums will apply equally to marine tanks. The best form for the latter is the shallow vessel with a slanting false bottom, described in a preceding chapter and illustrated by Figures 51 and 52.
If you have a common rectangular tank, such as can be purchased at any aquarium-store (Fig. 50), it may be rendered inhabitable for marine animals by making a few improvements. Four tall glass panels admit too much light; therefore give the outside of the glass a coat of green paint on all but one side, leave that clean and transparent to serve as a window, through which may be observed the interior and its occupants. The rockery or arch that is to occupy the centre of the aquarium should be cemented together with marine cement. Although this is not absolutely necessary, it is the best plan, and prevents many accidents. The following receipt I cull from the Scientific American:
Cement for Marine Aquaria.—Take 10 parts, by measure, litharge, 10 parts plaster-of-Paris, 10 parts dry white sand, 1 part finely powdered resin, and mix them when wanted for use into a pretty stiff putty with boiled linseed oil. This will stick to wood, stone, metal or glass, and hardens under water. It resists the action of salt water. It is better not to use the tank until three days after it has been cemented.
The arch may be built out of clean cinders or ragged and irregular stones; an old oyster-shell with its rough side uppermost can be used as a top-piece. To make the arch steady and not liable to upset, the bottom should be composed of rather large flat stones.
Cover the bottom of the aquarium to a depth of an inch or more with sand from the beach. Procure the salt water from the ocean itself, and if possible obtain the supply some distance from shore. In no case must you dip the water for your aquarium up from the mouth of a fresh-water stream or muddy creek. If the tank is narrow and deep, fill only about one-third of it. Let the water stand in the aquarium for several days before introducing the plants. Select the bright algæ or seaweeds that you find attached to small pebbles; the stones will of course sink to the bottom of your aquarium and keep the plants in an upright and stationary position. After all is arranged to your satisfaction, choose a place for the location of your tank where there will be light enough to plainly see its contents and cause little bubbles of oxygen to collect and rise from the vegetation. A window facing the north or northeast is the best situation. When you observe that the plants are in a thriving condition, and that a new vegetation has apparently sprung spontaneously into existence, carpeting the rockery and sides of the glass with green, then and not until then introduce the animals. Be very careful not to overstock the tank. Remember, no matter how bright and pleasant a room may be with one or two persons in it, the atmosphere of that same room will become foul and heavy in the presence of a large crowd, and if the ventilation be insufficient, headache, dizziness, and death will ensue, as was the case in the terrible Black Hole of Calcutta. Unless you want to make a miniature "black hole" of your aquarium, do not overcrowd it. Let the water have light, but no sunshine. Put a glass cover over the tank to keep out the dust, but let the cover fit loosely enough to allow a free circulation of air. The glass top-piece will in a measure prevent evaporation. If, however, any water is lost from this cause, recollect that the salts contained in sea water do not evaporate, and consequently the tank may be replenished with fresh water equalling the amount evaporated. Beware of the hot summer months. I have always found it more difficult to keep the water pure during July and August than any other part of the year. Do not allow smoking in the room where your aquarium is, as the foul atmosphere taints the water. I once lost almost all the inhabitants of a thriving marine tank, by allowing a party of gentlemen to smoke in the room where it was standing. If you have company in the evening, the room, as a rule, will become overheated, and you should take the precaution to wrap the sides of the tank with wet towels.
The prepared food mentioned in the preceding chapter will answer for some salt-water animals. Lean beef, cut in very small bits, may be dried and kept for feeding marine pets when oysters or clams cannot be had. The clams and oysters should be chopped up very fine when used. Anemones and madrepores should be fed in quantities regulated by the size of the animals, and not more frequently than once a week. The food should be placed gently within their reach by means of a pair of forceps or some similar instrument. Crabs will soon learn to come out of their hiding-places at meal-times, and the fish will not be behind time in getting their share of chopped clam. If you have a vivarium (Figs. 51 and 52), a handful of fiddler-crabs may be kept upon your artificial beach, where they will soon make themselves at home and afford a constant source of amusement by their antics. I kept a lot of little "fiddlers" in a fish globe, and for more than a year they lived without salt water, happy and contented with a bit of damp sand to dig in and an occasional piece of chopped oyster to eat. It would be difficult to find odder or more easily satisfied pets than the grotesque little fiddlers. Each male crab has one large claw which for exercise or amusement he keeps in constant motion, only folding it up when preparing to enter his hole or scamper sideways across the sand. The pedunculated eyes of these little creatures stand up in a manner that gives them a very pert appearance.
Remove all dead animals or particles of food not devoured by the inmates, from the aquarium, to prevent the water from becoming tainted with poisonous gases emanating from the decaying animal matter. Dead vegetation, though not as injurious as dead animals, should nevertheless be removed, for it is unsightly, and makes the water turbid and muddy. No matter how foul sea-water may become, you must not waste it, for the injury is never permanent, and can soon be remedied by filtering or exposing it in earthenware vessels to the air and gently stirring it occasionally with a stick or piece of glass.
A filter may be made of a flower-pot, by stopping up the hole in the bottom with a perforated cork in which a small quill has been inserted, and then filling the pot half full of powdered charcoal, sand, and gravel—the charcoal at the bottom, the sand next, and the fine gravel or coarse sand on top. This filter when in use should be hung over, but some distance above, an earthen-ware dish, and the water allowed to fall drop by drop, or in a small stream, from the pot to the dish, or the filter may be hung over the aquarium, and each drop of water as it falls will carry with it into the tank below particles of the purifying, life-giving oxygen gathered up on its journey through the air.
