The Book of the Aquarium/Part 1/Chapter 3

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Rockwork claims the first consideration when we proceed to fit up and furnish a tank. For a fresh-water aquarium, I do not recommend rockwork of any kind; and in the case of a vase, rockwork is positively dangerous, from its weight, and, unless very skilfully managed, will be ugly rather than ornamental. In the marine tank a few pieces of rock add to the beauty of the scene and the comfort of the creatures.

In fitting rockwork, some amount of taste and judgment must be brought into exercise. Shells and filagree work are largely used by some folks; but they belong properly to the child’s aquarium—they suggest dolls and battledores. Some rough fragments of any kind of non-metallic stone may be built up into a dark arch, or piled up after the fashion of a cromlech—one flat piece resting on two or three vertical pieces, so as to form a rude table-like structure. These may be fixed firmly in the places they are intended to occupy by means of Roman or Portland cement, which can be purchased at any building yard. The cement should be made into a stiff paste, and worked into the form required. Indeed, the rockwork may be wholly composed of such cement, especially if it is to have the form of an arch. The most important matter in the construction of rockwork is to give it a natural, rugged appearance, and to avoid loading the tank with superfluous weight. I have seen large shells and branches of coral in fresh-water tanks, and always thought the spectacle disgraceful to the owner. In a marine tank, such things are proper enough. Whatever is done should be made secure, the pieces of stone well embedded in cement, and the whole firmly united. The tank must be well seasoned, be frequently filled and emptied, to dissolve out any free salts before being put to use.

The Bottom must be composed of coarse river sand and small pebbles, the whole well washed before being introduced to the tank. Mr. Gosse condemns red sand and silver sand, as certain to stain the water. But I have two tanks now at work, both bottomed with such material, and the water preserves a crystalline brightness. I have also a marine tank, in which the bed is formed of common silver sand and garden pebbles: it has been in use nine months, and with no unfavourable results. In each case the sand was washed till the water could be poured away quite clear, and no matter what kind be used, the washing must be attended to. The coarser the grit the better its appearance, and, therefore, I do not recommend common sand, I merely show that it may be used when better is not attainable.

Mould has been extensively recommended as a bottom for tanks. I used it myself till I became convinced that it could be dispensed with altogether. It necessitates frequent changing of the water for at least a fortnight after the first stocking of the tank, in order to get rid of the soluble vegetable matter, which the water dissolves out of it, and its presence promotes the growth of confervæ, and other low forms of aquatic vegetation, that become obnoxious to the sight, and even hurtful to the health of the collection. I now use sand and pebbles only, and I find that aquatic plants of all kinds root freely and flourish in it, and, indeed, if pebbles only be used, they flourish just as well if their roots are covered.

Planting is next to be performed. The arrangement of plants will depend on the shape and size of the vessel. Generally speaking, massive plants look best if set back with lighter plants before them, just the same as a painter sets his chestnuts and elms in mid-distance, and his lady birches in the fore-ground. Stratoides, Potamogeton, and other plants of a massive and decided character, are well seen through the interstices of Myriophyllums, Callitriche, and such like fragile and delicate structures. The flowering rush makes a fine centre piece for a vase, and appears to good advantage when seen through an archway, in a tank containing rockwork.

If there is a bed of two or three inches of sand, the roots may be gently pressed down into it, and a few clean pebbles laid over the spot to keep the plant in its position. Some plants will require a stone to be attached to them by means of a thread to fix them properly. Crowns of Stratoides that have not formed roots, may be planted in this way. First cut away any black or decaying matter from the stem, and pull off any discoloured leaves, taking care not to injure the centre, then pass a piece of bass round the base, and attach a small stone. The plant will remain firmly where placed, and will throw out roots, and fix itself before the rotting of the bass takes place. It will then throw up new crowns and become a very ornamental object. Loose stems of Chara, Anacharis alsinastrum, or Callitriche, may be gathered together, fixed by means of a stone in the same way, a strip of bass being better than string for attaching them. They will generally get well rooted in a fortnight, and remain firmly where planted.

The Water should be pure and bright when introduced to the tank, and if the supply is at all faulty, it will be best to pass it through a filter before using it. 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.

In filling the tank, hold a plate in the left hand, as low down as possible, to receive the dash of water from the vessel in the right, so as to wash up the sand as little as possible. A syphon may be used if a source of supply is near the position of the tank.

Aspect.—Sunshine is good for the tank at all seasons of the year. But in high summer it should have only an hour’s sun, morning and evening; the fierce solar heat of mid-day will give the water so high a temperature as to be fatal to its animal inhabitants. Comparing tanks one with another, I must give a preference to a south or east aspect. A north aspect will do very well, from May to October, but, during the winter months, a tank in such a position, would be feeble, and want watching. Good exposure to daylight is, of course, essential; but it should be borne in mind that the fresh-water tank needs more light than a marine one. My fresh-water tanks I find to prosper best when placed close to the windows, but marine tanks may be kept back two or three feet, in a south aspect. In fact, if you have a cabinet of water-insects in a series of jars, the marine tank may very well stand behind them, and get sufficient light there, but the light should fall uninterruptedly on the fresh water vessels.