In procuring fish for the aquarium, one of the greatest sources of pleasure will be the catching of them. The catching of small fish, under ordinary circumstances, is an insipid and to some a very distasteful occupation; but when it is done for purposes of study, or with a view to the stocking of an aquarium, a new element of pleasure is infused into the pursuit. Our streams and ponds abound with little fish that are easily caught, and make very interesting little pets. The simplest and best way to capcure them is with a small net made of "mosquito netting." The net is simply a bag stretched on a hoop about 18 inches in diameter,which in turn is fastened to a handle six or eight feet long. The bag should be at least twice as deep as long; and if the netting is new and white, it should be stained a dirty mud-color by means of logwood or coffee, as the glare of the white net would scare the fish. The fish may be driven into such a net, or it may be used like a landing-net. No great dexterity is required, and it is a matter of considerable interest to examine the "haul" and sort out the different species. The angler should in this case be satisfied with two or three of a kind, and all the others should be returned to the water. Remember that many of these fish are the young of larger ones, and when full grown afford good sport to the angler. And even if they are not the young of the larger kinds, they form the natural prey of the food-fishes, and should be carefully protected from wanton destruction.
The varieties that may be obtained are quite numerous. There are the minnows, the dace, the darters, and others. Very small perch and sunfish form very handsome pets in the aquarium, but they must be quite small or they will prove mischievous. Pickerel and bass can only be admitted while very young, and in association with fish much larger than themselves. They should be liberally supplied with very small fish; or if allowed to become hungry they will torment and even kill fish ten times their size.
Gold and silver fish and the different varieties of carps all form interesting additions to the stock. These may be procured from the dealers for a very small sum. A very small eel is a curious and amusing little creature, and should by all means be allowed a place, although Edwards denies them admission on the ground that they kill the mollusks.
But of all the fish that are procurable under ordinary circumstances the stickleback is the most interesting; and the following account of its habits and mode of caring for its young can hardly fail to tempt those whose tastes lead them in this direction to repeat these observations. Mr. West gives the following account of his experience with a pair of sticklebacks: -
"In the spring of 1860 I procured some male and female sticklebacks, a single pair of which I placed in a fresh-water aquarium by themselves; and the remainder I deposited in a large salt-water tank, which was already pretty well stocked. The males of these quietly took possession of spots eligible for their nests and commenced building. They were, however, so much disturbed, and their work was so often destroyed by the crabs and other inmates of the aquarium that my experiment of breeding in my salt-water tank was for the season a failure. Not so in the fresh water one. The male promptly selected a home for his expected family, taking all the labor upon himself. Here, again, poetry has been substituted for fact. Instead of ' gently alluring his mate to their new-made home,' and being 'a model husband,' truth compels me to say that he was the veriest of tyrants, and fiercely attacked his cava sposa if she dared to approach the nest during its construction. When his labor was completed, however, he as harshly attempted to drive her into it. During the progress of the building her meekness, submission, and affection were beyond all praise. She generally lay quietly in a corner of the aquarium, and when he chanced to come near her would immediately rise up perpendicularly, quivering her fins, rubbing herself against his side, and making every possible demonstration of tenderness. All the material for the nest was conveyed by the male in his mouth. It consisted of various conferva?, stems of nitella, etc., which were placed in layers, with a mouthful of sand or fine gravel occasionally dropped upon them to keep each layer in its place; and he frequently slowly rubbed himself over the whole mass, apparently covering it with a cement exuded from his body. When completed it was a compact nest, with a round passage through it of from one fourth to three eighths of an inch in diameter. Having given it the finishing touch, he sought the female to drive her in. As I was at this moment watching the operation I had the rare opportunity of observing the actual depositing of the spawn, etc., of which no description has yet met my eye. The madam now acted with proverbial female coquetry and waywardness, and led her imperious spouse a chase a dozen or twenty times around the aquarium, avoiding the nest as obstinately as she had before eagerly sought it. At length she relented, and entered it at the orifice nearest the front of the aquarium. Her caudal fin alone remained visible, and I noticed that it had an incessant quivering motion. The depositing of the spawn lasted about forty seconds, and it was while the male excitedly hovered near that he almost literally 'turned as white as a sheet.' As she glided out at the further orifice he entered and performed his functions, also passing through the nest. Afterwards he closed the orifice and commenced an assiduity of attention to the nest that was most surprising. Night and day he kept guard over it for some eighteen days, - now strengthening its walls by additional stems of nitella, now thrusting his nose into the orifice to ascertain that the seal had not been violated; and every few minutes hovering over it, with his body inclined at an angle of forty-five degrees, fanning it with his pectoral fins, aided by a lateral motion of his tail. At length the young appeared, and the vigilance of M. gasterosteus was redoubled. On the day that I first saw the young ones, which I am pretty sure was the first day of their appearance, the delighted paterfamilias would not permit any of them to leave the mouth of the nest, the orifice to which he had torn open for them. On the second day their ' area of freedom' was slightly extended; but if they went beyond the limits he would take them in his mouth, as a cat does her kittens, and put them back into the nest. After a few days, however, he no longer restrained them of their liberty. Left to themselves, they soon spread themselves over the tank. I estimated their number at more than two hundred. From the time his parental duties ceased began the decadence of the male's brilliant coloring. As for the female, seemingly conscious that her functions were entirely at an end, she lay at a remote part of the tank, concealed by a root of vallisneria, never venturing near her husband and children. In fact, when the young fry began to extend their travels, and were seemingly able to take care of themselves, I removed both the parents for fear of accidents, to wit, possible infanticide, - a precaution I recommend in all similar cases. With such positive evidence that the male stiekleback alone 'attends to the little ones,' I could only smile when Mr. Hancock, a naturalist of some eminence, asserted, in an interesting and otherwise very correct description of this process of nidification which appeared in The Zoologist, that 'it required all the mother's unremitting exertions, for several days after the fry were hatched, to keep them within bounds, so as to preserve them from danger.' Even Dr. Lankester falls into a similar error, publishing with his endorsement a communication from a correspondent who describes 'the mother fish' as 'continuing her attendance at the nest as long as any of the young fry were left.' As the correspondent was a woman, the mistake was a natural one."
Fish in a well-arranged tank require very little food beyond that which is naturally produced in the water in which they live. Certain minute crustaceans (Cyclops, water-fleas, etc.) breed with marvelous rapidity; and as they feed upon the almost invisible animalcuhe, which in turn convert decaying vegetables into their food, a certain round or cycle of organic life is thus kept up. The eggs of snails also furnish a favorite food; and if a few "wigglers" can be procured and thrown into the tank the fish will rarely allow them to develop into mosquitoes. The plants also will furnish a certain amount of food, and a worm or two occasionally may be given to them by way of "entree." The dealers furnish a kind of wafer that answers well for most fishes; and we have found that goldfish, carp, minnows, and vegetable feeders in general are very fond of boiled rice. They eat it greedily, and thrive upon it. The rice is boiled in water until quite soft, then drained nearly dry, and, of course, given when quite cold. The boiled rice-grains resemble grubs in appearance, an 1 the fish make for them at once. One great advantage of boiled rice is that it has very little tendency to corrupt the water.