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A FRESH WATER AQUARIUM.

BY A. W. ROBERTS.

Many fresh-water plants have a tendency to grow above the surface. When this takes place, the leaves become so different in shape that they can hardly be recognized as belonging to the same plant. Therefore care must be taken to keep all plants submerged that are intended to supply air for the fish.

MERMAID-WEED.

One of the most common plants is the mermaid-weed (Proserpinaca). I have drawn it submerged and out of water, to show the change in the leaf. It grows along the margins of ponds that partially dry up in summer.

WATER-THYME.

Water-thyme (Anacharis canadensus) grows in slow-flowing streams. It requires coaxing to establish it in an aquarium, but when once rooted, is apt to grow too fast, requiring thinning out. Heap plenty of gravel on the root ends. Do not tie the bunch with string, as it will cause it to decay.

NITELLA.

Nitella flexis is almost a rootless plant, and will grow without any care. It is found growing in shady parts of cool ponds, streams, and lakes.

FONTINALIS.

Fontinalis antipyretica grows in springs and cool, shady ponds. It resembles a very fine and long moss. In color it is of a beautiful light green. I have often stored up quantities of this plant during summer (it becoming perfectly dry), that I might have it for winter use, and when placed in an aquarium it started out as fresh as ever.

DUCK-WEED.

Duck-weed, or duck's-meat, is a small floating plant, covering the surfaces of ponds and lakes in shady places. It is one of the best surface plants for producing shade, or for cutting off light that enters from the top of the water. Its thousands of rootlets afford hiding-places for numerous small aquatic animals, such as the hydra, crimson water-spider, and the brick-maker.

A small stone should be tied to each bunch of plants, to anchor them till they take root.

After your aquarium has been in operation a few days, a green coating will begin to form on the glass. This is a minute plant that is developed by the action of light. It can be removed by means of a swab. In all other parts of your aquarium allow it to grow, as it is the favorite food of gold-fish and snails.

SNAILS.

I have given drawings of the two best kinds of snails. One is shown with its broad foot expanded, by which it moves along the surface of the water, or on the glass when eating the green coating spoken of. Snails also eat decaying vegetable matter.

For keeping the water very clear, introduce a small-sized fresh-water mussel. Give him at least two inches of sand, in depth, in a corner of the tank, to burrow in, but watch him well, for if he dies without your knowledge your aquarium will be ruined.

CADDIS-WORMS.

In the illustration are figured three kinds of caddis-worms. These worms are useful for consuming decaying animal matter. When a "cad" has grown too large for his house, he makes a little case of silk, which he covers at each end with pieces of leaves, wood, or straw, biting them to the right length; some fasten on small bits of stone and shells. However rough the outsides of their houses may be, the insides are smooth, and lined with silk. When he changes into a chrysalis, he crawls up a plant, and closes up both ends of his house with a strong net-work of silk, which allows the water to pass through, but prevents the entrance of enemies. As he has taken care to place himself near the surface of the water, he easily escapes when he comes forth a four-winged insect resembling a small moth.

APPLE-SMELLERS.

Apple-smellers, or merry-go-rounds, are very interesting. They are of an intense shining black in color, and generally school together, moving in circles, with great rapidity, on the surface of the water. They are called apple-smellers on account of the strong odor they possess, resembling that of apples or quinces, and merry-go-rounds on account of their merry circling motions around one another. Young apple-smellers live on the bottoms of ponds, and look like centipedes. When the time comes for them to change into real apple-smellers, they climb up a plant, and make small bags of gray paper, into which they fasten themselves till they get their swimming legs and shining black new clothes, after which they burst open the paper bags, and swim off to join their friends gliding so merrily on the surface of the pond. When an apple-smeller dives to the bottom of a pond to take a rest or to feed, he attaches a globule of air to his tail (see cut); this he breathes while under water.

STICKLEBACKS.

The nine and the three spined sticklebacks are, without doubt, the most wonderful fish for their size that are common to our waters. They will live well in either fresh or salt water aquaria, building nests and raising their young under all discouragements. The male builds the nest for the female to lay her eggs in. The nest is composed of plants cemented together with a glue provided by the male, who also carries sand and small stones to the nest in his mouth, with which he anchors it. During the breeding season the male assumes the most brilliant hues of blue, orange, and green; previous to this season he is of a dull silvery color. When an enemy approaches the nest, be he large or small, he will attack him, inflicting wounds with his sharp spines. Nor will he allow the mother of the young sticklebacks to come near, as she is so fond of her babies that she often forgets herself and eats them up. When the young "tittlebacks," as they are often called, swim too far from the nest, the male takes them in his mouth and brings them back, throwing them out with such force that they make many somersaults before landing. Sticklebacks are the smallest known fish when first hatched out of the egg, being nearly invisible.

DRAGON-FLY.

Here is the dragon-fly, as he looks before he gets his