A Study Of Fishes
( Originally Published Ealry 1900's )
While observing a living fish and admiring its beauty, it will probably occur to some of us that a fish consists only of a head and tail. Yet this is not all. Between the head and tail is a part that we may call the trunk. It contains the digestive and other organs. There is no indication of a neck in a fish. Any such constriction would destroy the regular outline of the animal's body and thus retard the speed with which it moves through the water. But head, trunk and tail are not all. There are attached to the outer side of the fish's body certain appendages that are called fins.
Before discussing some of the different kinds of fishes and their habits, it will be necessary to learn something about fins, for the fins of all fishes are not alike. When a fish moves through the water, it bends its tail first to one side and then to the other. This undulatory movement, as it is called, pushes the fish's body ahead. One can observe the movements easily upon a specimen kept alive in an aquarium jar. At the extreme end of the tail there is a broad, notched fin which aids the tail in propelling and steering the body. We will call this the tail or caudal fin. In most of our common fishes there are seven fins — six without the caudal. The first of these six is a large fin situated near the middle of the back. This is the back or dorsal fin. Sometimes we may find a fish that has two dorsal fins. In this case the one nearest the head is called first dorsal and the next one behind it the second dorsal. Near the head, in a position corresponding to our arms, is a pair of fins which are called the arm or pectoral fins. Farther back towards the tail, on the under side of the fish, is another pair, corresponding in position to the hind legs of a quadruped. This pair is called the leg or pelvic fins. Just behind the pelvic fins is a single fin, situated on the middle line of the body. This is the anal fin. The pectoral and pelvic fins are called paired fins because they are in pairs. The others which are not in pairs are called median fins, because they are situated on the middle line of the body. The paired fins serve as delicate balancers to keep the body right side up and to regulate speed. They are also used to propel the body backwards. After naming the different fins of the fish in the schoolroom aquarium, it will be interesting to observe the uses of each.
On the side of the body, extending from the head to the caudal fin, is, in most fishes, a line made up of a series of small tubes which open upon the surface. This is called the lateral line, and acts in the capacity of a sense organ. Is the lateral line straight or curved? Does it curve up-wards or downwards? Does the curvature differ in different kinds of fishes? Do all the fishes you find possess a lateral line? Is the lateral line complete in all fishes, i. e., does it extend from the head to the caudal fin with-out a single break?
Where Fishes Spend the Winter.—As winter approaches and the leaves fall and the ground becomes frozen, the birds leave us and go farther south into warmer climates where food is more abundant. We are all familiar with this habit of the birds, but how many of us know or have even wondered what the fishes have been doing through the cold winter months while the streams and ponds have been covered with ice? Before the warmth of spring comes to raise the temperature of the streams, let us go to some familiar place in a brook where, during the summer, are to be found scores of minnows. None are to be found now. The brook shows no signs of ever having contained any living creatures. Suppose we go farther up or down the stream until we find a protected pool the bottom of which is covered with sediment and water-soaked leaves. With our net we will dip up some of the leaves and sediment, being sure that we dip from the very bottom. On looking over this mass of muddy material we may find a fish two or three inches long, with very fine scales, a black back, a silvery belly and a blackish or brown band on the side of the body extending from the tip of the nose to the tail This is the Black-nosed Dace. If specimens of this fish are caught very early in the spring, one will be able to watch some interesting color changes. As the spawning time approaches, the dark band on the sides and the fins change to a bright crimson. Sometimes the whole body may be of this gaudy color. During the summer the lateral band becomes orange. . As the season goes, the bright colors gradually fade until finally, in the fall and winter, the little black-nose is again clothed in his more modest attire. A great many of the fishes, and especially the larger ones, seek some deep pond or pool in the stream at the approach of winter, and remain near the bottom. If the pond or stream is so deep that they do not become chilled they will remain active, swimming about and taking food all winter. But when the stream is very shallow and the fishes feel the cold, they settle down to the bottom, moving about very little and taking little or no food. The carp collect in small numbers and pass the winter in excavations that they make in the muddy bottom. If the debris thrown up by the water across the marshy end of a lake be raked over during the winter, one will probably find some of the smaller catfishes spending the season in a semi-dormant state.
Some interesting experiments may be tried with the fishes in the aquarium jar. Keep them for a few days where it is cold and then bring them into a warmer room and note the difference in their activity.
The Common Catfish or Bullhead.— This sleepy old fellow differs in many respects from most of our common fishes. He has no scales. About the mouth are eight long whisker-like appendages, called barbels. Perhaps he is called catfish because he has whiskers about his mouth like a cat. Any one who has ever taken a catfish - from the hook probably knows that care is needed in order not to receive a painful prick from the sharp spines in his pectoral and dorsal fins.
There is nothing aristocratic about the catfish. In warm pools and streams where the water is sluggish and the muddy bottom is covered with weeds, he may be found moving lazily about in search of food. His taste is not delicate. Animal substance, whether living or dead, satisfies him. When in search of food he makes good use of his barbels, especially those at the corners of his mouth, which he uses as feelers. The catfish will live longer out of water than most of our other food fishes. They will live and thrive in water which is far too impure for " pumpkin seeds " or bass. They spawn late in the spring. The mother fish cares for her young much as a hen cares for her chickens. When they are old enough to take care of themselves, she weans them.
The Common, Sunfish or Pumpkin Seed.—Some evening just at sunset visit a quiet pool in a nearby stream. Drop in your hook baited with an " angle worm " and presently the dancing cork shows that you have a " bite." On " pulling up," you find that you really have a fish. It is a beautiful creature, too—thin flat body shaped something like the seed of a pumpkin. His back is an olive green delicately shaded with blue. His sides are spotted with orange, while his belly is a bright yellow. His cheeks are orange-color streaked with wavy lines of blue. Just behind his eye on- his " ear-flap " is a bright scarlet spot. This is the common Sunfish or Pumpkin Seed. He is a very beautiful, aristocratic little fellow, " looking like a brilliant coin fresh from the mint."
Keep him alive in an aquarium jar with a shiner. Compare the two fishes, as to the size and shape of their bodies and fins. Feed them different kinds of foods, such as worms, insects and crackers, and try to discover which they like best and how they eat.
The sunfishes prefer quiet waters. They lay their eggs in the spring of the year. The male selects a spot near the banks of the stream or pond where the water is very shallow. Here he clears a circular area about a foot in diameter. After making a slight excavation in the gravel or sand, the nest is completed. The eggs are then de-posited by the female in the basin-like excavation. He watches his nest and eggs with great diligence, driving away other fishes that chance to come near.
The Black Basses.—The black basses are not usually found in small streams where it is most pleasant for teachers and pupils to fish. They are fishes that seek the rivers and lakes. There are two kinds of black bass, the Large-mouthed and the Small-mouthed. As the name indicates, the two may be distinguished by the size of the mouth. In the large-mouthed black bass the upper jaw extends to a point behind the eye, while in the small-mouthed species it extends to a point just below the middle of the eye.
Both kinds of black bass may be found in the same body of water. The character of the bottoms over which they are found, however, differs. The small-mouthed prefers the stony bars or shoals. The large-mouthed, on the contrary, selects a muddy bottom grown over with reeds. They feed upon crayfish (" crabs "), minnows, frogs, worms, tadpoles and insects. Our black basses are very queer parents. They prepare a nest in which the eggs are deposited. Both male and female are very courageous in the defense of their eggs and young. As soon as the young fishes are able to take care of themselves the parent fishes leave them, and after that time may even feed upon their own children.
The Stickleback.— The sticklebacks are queer little fellows indeed. The slender body, extremely narrow tail, and the sharp, free spines in front of the dorsal fin, give them at once the appearance of being both active and pugnacious little creatures. The sticklebacks are detrimental to the increase of other fishes since they greedily destroy the spawn and young of all fishes that come within their reach. They build nests about two inches in diameter, with a hole in the top. After the eggs are laid the male defends the nest with great bravery. The little five-spined brook stickleback is most commonly found in stagnant pools, shaded by trees, where the water is filled with decaying vegetable matter,—the so-called " green frog-spawn " (spirogyra), and duck weed. If you supply the sticklebacks with plenty of fine vegetable material, you may induce them to build a nest in the aquarium jar, but they must be caught and placed in the jar early in the season before they spawn.
The Johnny Darters.— In New York State, every swift stream which has a bed of gravel and flat stones ought to contain some one of the Johnny darters, for there are a great many different kinds. They are little creatures, delighting in clear water and swift currents where they dart about, hiding under stones and leaves, or resting on the bottom with their heads up-stream. The body of a darter is compact and spindle-shaped, gradually tapering from the short head to a narrow tail. The eyes are situated nearly on top of the head. The color of the darters varies greatly with the different kinds. Some are very plain, the light ground color being broken only by a few brown markings. Others are gorgeous in their colorings, it seeming as if they had attempted to reproduce the rain-bow on their sides. Such kinds are indeed very attractive and are ranked with the most beautifully colored of all our common fishes. When a darter swims, he appears bird-like, for he flies through the water much as a bird flies through the air. He does not use his tail alone in swimming, as the catfish, the sunfish, the stickleback, and most of the other fishes do, but flies with his pectoral fins.
You surely must have a Johnny darter in your aquarium jar. The Johnnies are true American fishes. Though small, they face the strong currents and eke out a living where their larger cousin, the yellow perch, would perish. There are many interesting facts which may be learned from the Johnny darters when kept alive in an aquarium. When not actually moving in the water, do the Johnnies rest on the bottom of the jar or remain suspended in the middle apparently resting on nothing, as the other aquarium fishes do When a fish remains still in the middle of the jar he does so because he has a well-developed air-bladder to help buoy him up, and when a fish dies it is the air-bladder which causes him to turn over and rise to the top. Now if the Johnnies always rest on the bottom of the jar when not swimming and if one happens to die and does not rise to the top we may know that, if he has an airbladder at all, it is only a vestigial one. It would be interesting also to find out for ourselves whether a Johnny darter can really ` climb trees " (I mean by' trees, of course, the water plants in the aquarium jar), or if he can perch upon the branches like a bird.
The Minnows.— All the small fishes of the brooks are called minnows, or more often " minnies, " by the boy fisherman. The boy believes that they grow into larger fishes. This is not true. The minnows are a distinct group of fishes and, for the most part, small ones. They do not grow to be bass or pike or sunfishes or anything else but minnows. Some of the minnows, however, are comparatively large. Two of these are the Creek Chub and the Shiner. The chub is the king of the small brooks, being often the largest and most voracious fish found in such streams. His common diet probably consists of in-sects and worms, but if very hungry he does not object to eating a smaller fish. During the spawning season, which is springtime, the male chub has sharp, horny tubercles or spines developed upon the snout. We are able to recognize the creek chub by means of a black spot at the front of the base of the dorsal fin.
The shiner or red-fin has much larger scales than the chub. The back is elevated in front of the dorsal fin, giving him the appearance of a hump-back. His sides are a steel-blue with silvery reflections. While the, shiner is not the largest, it is almost everywhere one of the most abundant brook fishes. In spring the lower fins of the male become reddish. Like the chub, he has small horny tubercles developed on the snout.