Fig. 64. Snail with conical shell.
Animals that may be kept in aquaria.—The snail. The common pond snail with the spiral shell, either flat or conical, can be found clinging to the stems of the cat-tails or flags and to floating rubbish in ponds or swamps. If these are picked off carefully and taken home in a pail of water they will be valuable inhabitants for the aquarium. They are vegetable feeders and unless there is some green slime in the water, cabbage or lettuce leaves may be put where the snails can get them. The eggs of the snail are excellent food for fishes, and if a few could be secured for special study, their form, habits and development may be made delightful observation and drawing lessons. Snails can be kept out of the water for some time on moist earth. Land snails and slugs should be kept on wet sand and fed with lettuce and cabbage leaves. The common slug of the garden is often injurious to vegetation. It may always be tracked by the trail of slime it leaves behind it. Gardeners often protect plants from those creatures by sprinkling wood-ashes about them.
Minnows. Every boy knows where to find these spry little fellows. They can be collected with a dipper or net and will thrive in an aquarium if fed with earth worms or flies or other insects. If kept in small quarters where food is scarce, they will soon dispatch the other occupants of the jar. They will, however, eat bits of fresh meat. If the aquarium is large enough, it would hardly be complete without minnows.
Cat fish.—It will not be practicable to keep a cat fish in the permanent aquarium. If one is to be studied it can be obtained at any fish market or by angling, the latter a slow method, but one which will appeal to every boy in the class. The cat fish should be kept in a tub, tank, or large pan of water, and if not wanted for laboratory work, they might be fried for lunch, as cat fish are very good eating.
Gold fish are a special delight if kept in large aquaria. These may often be obtained from dealers in the larger cities. Those who wish other fish for study should be able to get information from the New York State Fish Culturist, concerning the species that are suited to life in still water, and how to get and take care of them.
Fig. 65. "Frog spawn."
The clam.—If empty clam shells are plenty on the bank of some stream after a freshet, a supply of clams may be obtained by raking the mud or sand at the bottom of the stream. They can be kept in a shallow pan, and if the water is warmish and they are left undisturbed for a time, they will move about. If kept in a jar of damp sand they will probably bury themselves. They feed on microscopic plants and might not thrive in the permanent aquarium.