Part 13

Carp will hurry to the top of the water to get food that they have learned to look for when people come near. Fish of a kind often keep together and feed together. You know in a stream there may be some places where you will catch only trout, or only bullheads. And in some other place you will find pickerel.

In the sea you will find millions of herring together at certain seasons. This is called a shoal of herring. Fish move from place to place along many miles of sea-coast or river, as they seek their especial food, or a certain warmth.

Sometimes a particular fish, or pair of fishes, will live for years in some certain place. They may find a nice spot under a bank, where they feel safe, and where plenty of food drifts near them.

I knew of a fish that went into a hole made by the roots of a great willow-tree. The roots formed a close cage about him. He liked it well. His enemies could not get at him. Water rippled in and out about him. Grubs and worms were close to his mouth. He grew fat and big. He grew so big he could not get out. He began to grow to fit the shape of his cage. As he had no room to grow long, he grew broad.

After some years he was a very queer-looking fish. Finally, some men were making an embankment, and they came upon this fish-home in the roots of the tree. They took the fish out with care, and sent him to a pond. I fancy it seemed odd to him to swim at first, after being so long a prisoner.

There are some kinds of fish that live and thrive in the icy-cold waters of polar seas. There are other fish that live in hot springs or ponds, where the water is so hot that you can hardly bear your hand in it.

Some fish can live only in very clean water. Others live in black and muddy streams, and their flesh takes the dark hue of their home. In fact, there seem to be some kinds of fish made to suit every kind of water. This is very fortunate, as so many birds and beasts and so many people eat fish.

FOOTNOTES:

[31] The dolphin of the Mediterranean is of the whale family, and is not a true fish. The dolphin of the Atlantic is a true fish. The porpoise is of the whale family, not a true fish, but a mammal.

LESSON XLIII.

HOW THEY BEHAVE.

Birds, beasts, and insects live where we can easily watch them. Wherever we go, they are our near neighbors. We can easily find out many facts about their way of living. For this reason, many people, from the earliest times, have observed these creatures, and have written down what they learned about them.

But of fish, people have been able to see and know much less. It has taken much longer to learn about creatures that hide in the waters, and are, for the most part, out of our sight. Seeing fish so much less often, people took less interest in them.

Since great aquariums were built with glass tanks, in which fish can live at ease and behave in a natural way, we have learned more of their habits.

These tanks are filled with salt or fresh water, as the fish may require. The floor of the tank is covered with sand, rock, shells. Then crabs and small “shell-fish” of many kinds, and larvæ and worms are put in, such as the fish would find in their native homes.

Caves and grottos, lined with moss and weeds, are built; and the tank looks like a true part of a river, pond, or sea. Then the water is kept at the right warmth, and fresh air is driven in as I have told you. The light is made just right for the fish in the tank, and proper kinds of fish are put together.

When you go and stand outside of one of these great tanks, this water world is before you from top to bottom. Now I shall tell you some of the things which I learned about how fish behave at home.

By such a tank I first learned that nothing can be more easy and full of grace and majesty than the motion of a fish in the water.

I watched a great fish swimming. I could not see the motion of a muscle, or the least quiver of fin or tail. His great round eyes shone; his splendid red fins were still; his spotted back glistened through the waves; his broad sides gleamed in silver mail.

He never seemed to stir from his majestic calm. He stole across the line of vision, but without visible effort. He crossed the path of other fish. He sailed above them or below them; but he seemed to feel himself all alone, and to notice nothing.

A fisher who had watched pike told me that, when he watched one lying in a pool, he was sure that the fish saw him. It did not seem to make any motion. But the fish changed its place. Soon it was gone.

In the next tank to the one I spoke of, were flounders. They swam with a wave-like motion of the whole body. They did not swim straight forward. They went up and down in curves. Their motion was much like the flight of short-winged, heavy birds. In fact, a sole which had its eyes and mouth set upon a kind of skull-shaped head, on the upper side of the flat body, looked much like a dim, first idea of a bird.

The fish in the tank were not fish that fed on each other, and they never seemed to notice each other at all.

I saw some kinds of fish asleep. A dog-fish lay asleep on the sand, with his nose in a corner, for half a day. He looked as if he were dead. Three hermit crabs[32] were crawling about over him. He never stirred. He did not seem to notice their sharp claws and their jostling shells.

This sleeping of the dog-fish reminded me of what I had seen in pools where fish lie basking in the sunshine. Some fish are very fond of lying in a sunny spot. Others will get into a shadow, and lie there with great content.

I found in my study of fish life in tanks, that fish are given to fighting. Some of them fight with their nearest relatives. In a small tank I saw two fish that fought and bit each other so cruelly that they had to be parted.

There had been several fish in this tank, and all but two had been killed in their battles. Then a glass partition had been put in the middle of the tank, and one fish lived on each side. They swam up to this clear wall, laid their noses against it, and glared at each other.

Another fact I remarked in fish is the clearness and keenness of their vision, and the quick way in which they will dart at food. When they see something that they wish to eat dropping down through the water, they spring at it with open mouths, and seem never to miss their mark.

When they need more air than they can get from the water, they swim to the surface and take a gulp of air and water. When they are sick, they do not swim, but lie on their sides, as if they feel too weak to make any effort. When they are dead, the bodies turn over and float on their backs.

It is said that fish can reproduce parts that they have lost, as crabs and star-fish can. At least, they can easily live when an eye or part of their mouth or a fin is gone. They seem to suffer little from such a loss. A fish that has a wound, or has just lost an eye, will swim about and eat as if it felt no pain.

Some fishes that live on the bottom have a queer way of lying close on the sand, with their mouths wide open. They pant as if in great pain. But they are not in pain, they are sifting their food out of the water.

Look into their throats, and you will see a network, like fine bones. That is their sieve to catch small food.

Some fish are timid, and hide at the least sound. Others are fearless, and lie in plain view, or boldly follow their prey. A fish darting after his food is a fine sight. His jaws are open; his spines stand in a ridge on his back; his eyes gleam. His whole body seems alert and full of fire.

You should watch fish for yourselves. You have seen gold and silver fish in globes. Other fish are often kept in ponds and fountains as pets. They become very tame. Sometimes they learn to know those who feed them, and will come when called.

FOOTNOTES:

[32] See Nature Reader, No. 1, Lesson 8.

LESSON XLIV.

FRY AND SCHOOL.

A fish comes from an egg, as a bird does. There are one or two kinds that are born as little live fishes. But the rule is that the fishes hatch out of tiny eggs. The mother fish drops these eggs in the water, or carefully lays them in some place which she prepares for them.

After they are laid, these eggs are called spawn. Before they are laid, they lie in a solid mass together. There are many thousands of them in each mass, and they are then called roe. I have told you of the wonderful number of eggs laid by insects. But fish surpass even the insects in the number of eggs.

These eggs are subject to very many dangers. Fish, crabs, and water-fowls eat them. The waves may dash them ashore, and so they will be dried up. Therefore it is needful that there should be a great many, so that after all disasters a large number may hatch.

The eggs of fish are of a pearly white, or a cream color. They are covered with a kind of glue, so that they stick together. They also stick to weeds, or rock, or sand, where they are laid.

There are very few fish that carry their eggs about with them, after they are laid. The fish presses its body against the eggs, which stick to it, and are carried about, until they hatch. You have read of the crab which took care of its eggs in this way.[33]

As the little fish grows within the egg, the soft skin-like case becomes very thin. When the time comes for hatching, the little fish breaks the case, and comes out. As a general rule, the little fish, just out of the egg, looks and acts like the parent fish. But there are some that change much between their first and their full-grown states.

Let us now look at some curious fish eggs and fish nests. Of all the fin family, the dog-fish has the most curious cradle for its young. The egg-case of the dog-fish is a horny bag, or purse. It is of a gray or blackish color, about an inch wide, and two inches long. At each of the four corners, it has a long, stiff, curly stem.

The mother dog-fish swims near the shore to lay her eggs. She selects a weed, branch, or piece of tree, lying in the water. To this she ties her egg-cases by means of their long stems, or strings. She does this by swimming round and round the twig to which she means to fasten the case. As she drops the case in the water, she ties it, or binds it, by drawing with her the curly ends, as she swims, about the branch.

She lays a number of these purses in a place. Then she swims off and leaves them. It is lucky that she does, for if she stayed near them, she would eat the little fish as soon as they came out!

I have seen a dog-fish tying its eggs to a branch lying under water, and it was a queer sight. When the baby fish has grown large enough to leave the case, it makes a little opening on one end, and creeps out.

The skate, that is a cousin of the dog-fish, lays a case much like this. But the case of the skate is of a shape more nearly square. It has four sharp, curved horns, not long, curly ends; and the little skate comes out of a hole in the middle, never at the end.

Another sea-fish, the mackerel, has no such protection for its eggs. It drops thousands of them on the water, and they look like tiny pearl beads. They sink to the bottom. As they are sticky, they cling together, and to the sand, until they hatch.

That prettiest of fish, the trout, which lives in so many clear, shady streams, where there are deep, quiet pools to bask in, is very careful of her eggs. The mother trout sinks to the bottom of some clean stream, and selects a nice sandy place. Then, with her tail, she fans out all the coarse sand and gravel. If there are larger bits of pebble, she carries them off in her mouth.

When she has made a nice smooth little nest, like a cup, she drops her eggs into it. Then she covers them lightly with gravel, so that they will not be floated away. When she has finished one nest, she swims off to make another.

The black bass of our lakes and ponds makes a smooth bed for its eggs. It prepares this bed in the shadow of a stone or sunken log. Several bass will go together, and select and clear out such a bed. Then they will lay their eggs there, and for days, until the eggs hatch, will swim about near, to keep watch over them. Eels, cat-fish, perch, and suckers, come to eat these eggs, and the big bass drive them away.

The pretty perch does not take such care as this of her eggs. She drops them in long chains, among grasses, and leaves of water-plants, at the edge of the pond. When the yellow cowslips are in bloom, you can find these eggs among the water-plants, like strings of fairy beads.

When the baby perch come from the eggs, they are very nimble, and begin at once to eat. When they are no longer than the nail of your little finger, it is funny to see them in the water, darting after the living atoms that serve them for food.

They see and know these tiny things in the water, and pounce upon them with wide-open mouths.

The little fish, from the time they are out of the egg, until they are about half grown, are called fry. Some fish, as the salmon, get different names at different periods of their growth. A great many fish together are called a school. Thousands of fish will come leaping, rolling, and tumbling along in the water, and we say it is a school of fish.

FOOTNOTES:

[33] Nature Reader, No. 1, Lesson 3.

LESSON XLV.

SCALES AND TEETH.

I told you that most fish had scales, and that these scales clothed them in a gleaming, flexible suit of armor. Most of the beautiful color of fish is found upon their scales. Many of the scales are iris or rainbow hued. That is, they have the gleam of many colors, according as the light strikes them. Have you not seen such colored light in a glass prism?

The scales of different fish vary in shape, size, color, and hardness. In general, they are horny like your finger nail, but thinner. Their shape is nearly round, much like a rose petal. They are fastened by the smaller edge to the skin of the fish. Then each scale laps over the next one, and so on.

Scales are always so set that they turn or lap, from the head toward the tail. In the middle of each scale, on the lateral or side line of the fish, is a little groove or canal. It runs in the direction of a line from head to tail. Let us see what it is for.

Have you noticed how slippery fishes are? Is it not hard to hold them? If you rub your finger hard down their bodies, you rub off a quantity of slime, or stuff like glue, or thin paste. This glue-like stuff is made near the mouth of the fish. It is supplied to the scales by little tubes near the mouth. It runs through that little canal in each scale in a line upon the side of the fish.

This slimy stuff helps the fish to slide easily through the water. It keeps the scales limber and healthy. It keeps the body supple. It helps the fish to slip away from creatures that seize it. Also, I am sure, it helps the fish to slide easily down the throats of birds, animals, or fish that capture it!

The fact that the scales all lie turned from the head to the tail of the fish, also makes it easy for birds or other fish to swallow it. But if a fish is partly swallowed, it cannot be readily cast out, for its scales rising, make a rough surface, and hinder it. I suppose that was why the alwife duck I told you of could not get the partly swallowed fish out of her throat.

Each kind of fish has its own especial shape and color of scales. Some are pointed, some are rounded, some are flat, some are curved, some are three-cornered. Some fish have no scales. Some have such tiny ones that you will not notice them unless you look sharp. Some fish, as the sturgeon, have great bony plates, like large limpet shells, laid in lines up and down the body.

Fish not only have their own especial shape of scales, but their especial color, and such colors have their especial place on the fish. One flat, brown fish has all the under side of its body white, but spots of red, like sealing wax, are laid all over the brown side, as if you had dropped red wax upon it.

When you see a smoked and salted herring hung up for sale, you are not likely to guess what a beautiful thing it was, when living in its water home. It had a coat of blue, green, and silver, and gem-like eyes. The eye of a dead fish is sunken and dull. The eye of a living fish is full, and gleaming with light.

There is a little fish called a wrasse which looks as if made out of a rainbow. It is dressed in bright blue, gold, bronze, and white.

The red bream is of a fine rose-red color, with silver sides. Its luminous eyes are set in golden rings. The perch has dark, shining bands on its silver coat, and it has gay, red fins. The gray mullet is a quaker fish, trim, grave, quiet in its style, but lovely in its shape and in the rainbow lights along parts of its body.

Once I saw in the water a fish called a gurnard. He seemed to have borrowed a sunset to dress himself in. His scales were deep red and bronze. There was a vivid blue on the edges of his fins. The fins were in shape and coloring like a butterfly’s wings.

I never saw a boy who did not think that a trout was one of the prettiest things ever made. Very much of the beauty of fishes lies in the wonderful scales.

But you must examine scales for yourselves. If you have a microscope to look at them with, you will be full of delight and surprise at what you see. Once I looked through a very powerful microscope, and thought I was looking at a lump of half-melted gold set full of fine jewels. But it was the scale of a fish.

I will now leave the scales, and tell you a little about the teeth of fish. Fish have a great many teeth. Their mouths are for the most part hard and horny, and so covered with teeth that it is not likely that they have very much sense of taste. Still there are some kinds of fish that are almost, if not quite, toothless.

If you open the mouth of a sea-trout you will find that it is set entirely round, with sharp, strong teeth. Then if you stretch the mouth open and look into it, you will see that there is another row of teeth set all round a bone inside the upper jaw. Look still farther in, and you will see a row of teeth on the middle bone in the roof of the mouth. Look still beyond, and you will see a row of teeth on each side of the tongue.

Some fish, besides all these teeth, have the tongue quite covered with teeth. Others, that eat vegetables, have little fine teeth all down the sides of the throat. The French call such teeth as these, “teeth in the velvet.” Some fish have the entire mouth and throat lined with teeth.

These teeth may all be alike, not some “double” and some “single” as you have. But sometimes fish have teeth of different patterns. The most common form of teeth in fish that live on fish or other animal food, is that of a slim cone, bent a little inward to hold firmly the fish caught, so that it cannot slip away.

The fish that feed on weeds have short, roundish teeth with a flat top, to make a good mill with which to grind or crush their food. Fish that eat insects do not need such large teeth. They have a great number of little teeth almost as fine as hairs. Rows of these teeth look like a little brush.

Some fish are said to have “mill” teeth, as the carp, because their large flat teeth roll upon each other like the stones of a mill grinding grain.

The ray fish, that feed on crabs, shell-fish, and flat fish, need very strong teeth for crushing such food. If you should look into their mouths, you would see that they are made like a mill, and the upper and under teeth roll against each other and crush fine all that is between them. By looking at the mouth of fish and examining its teeth, you can find out what kind of food it used, just as by looking at the beak and claws of a bird, you can tell what were its habits and food.

Some fish have the inside of the stomach thick and furrowed, very like the gizzard of a fowl. This is to aid in cutting or grinding up the food. The teeth of a carp have much the appearance of the teeth of sheep and cows, only they are much smaller. They work against a plate of gristle in the roof of the mouth and reduce the food to pulp.

The strong, sharp teeth of fish are used not only for eating their food, but for biting and fighting other fish. Two great salmon have been known to fight until one was killed. The dead one was found to be badly wounded and torn by the teeth of its enemy.

Pike have very sharp, strong teeth, and a big pike has been known to seize hold of the foot or nose of a dog, fox, or other animal, that came to the water’s edge to drink.

The mouth of a dog-fish is set back on the under side of the head. This mouth has a row of strong, sharp teeth all round it. When the fish seizes its prey or its enemy with its teeth, it whirls itself over, and this action enables it to tear out a large piece of the flesh held by its teeth.

LESSON XLVI.

BIG AND LITTLE BROTHERS.

Yesterday, as I was going along the street, I saw a large globe full of tiny fish. They were from one to two inches long. I stopped to examine them. They were sticklebacks. You must know that little Mr. Stickleback is a very pretty and curious fellow, and well worth buying.

Looking into this globe made me think of some of the queer things I have heard and seen of this little fish. Shall I tell you about him?

The stickleback gets his name from the fact that some of his fins, one on the back and one on the lower part of the body, have changed to spines or thorns. Different kinds of stickleback have three, four, ten, fifteen, of these thorns.

This little fellow is one of the smallest and prettiest of fishes. He is slender, and from one to three inches long. The general length is about an inch and a half. His body is silver below, green and purple in bands on the back, and red and gold on the head and sides. His fins are thin as finest silk. I never saw a prettier little creature.

The stickleback is very greedy, very fearless, full of courage, very affectionate, and of all fishes is the most devoted parent. Finally, the stickleback can build a house.

The colors of the stickleback brighten or fade according as he feels glad or sad. If he has lost his mate, his home, or his young ones, or if he has been beaten in a fight, he swims off to hide, and his colors grow dull. If he has beaten his enemy, if his children and mate are quite safe in the little house where he has put them, he gleams and glows like a rainbow.

Sticklebacks are so fearless that when they are in a pond no noise or shadow will alarm them. You can even catch them without a hook just by dropping among them a string with a worm on it. You may pull up the string with two sticklebacks fast, one on each end of the worm. Little English boys take this way of catching these tiny fish for their globes.

When put into a globe or box, they fight sharply at first. They strike each other with their spines, whirl, dart, pretend to be beaten, and then leap back to the fight. They are real little soldiers. Finally, when they have found out which of them all is the strongest, each one chooses his own corner, or shelter by a stone for a home, and defends that against all strangers.

The different varieties of sticklebacks build different kinds of houses. One makes a nest like a muff among water-weeds. I will tell you of one kind of nest. The little fish carries straws and bits of grass and moss, and tucks them down into the gravel and sand. He glues them with the glue from his skin.

While he is at work he holds and carries his material with his mouth, and presses it into place with his body. Having laid a floor, he builds a little hut of woven fibres and moss. This hut is about as large round as a twenty-five-cent piece. A little door is at the top. He tries the strength of his house by stirring up the water near it with his tail.