"This is a noteworthy and characteristic lineament, or cipher, or hieroglyphic, or type of spring. You look into some clear, sandy bottomed brook where it spreads into a deeper bay, yet flowing cold from ice and snow not far off, and see indistinctly poised over the sand on invisible fins, the outlines of the shiner, scarcely to be distinguished from the sands behind it as if it were transparent."
HERE are many species of shiners and it is by no means easy to recognize them nor to distinguish them from chub, dace and minnows since all these belong to one family; they all have the same arrangement of fins and live in the same water; and the plan of this lesson can with few changes be applied to any of them.
Never were seen more exquisite colors than shimmer along the sides of the common shiner (Notropis cornutus). It is pale olive-green above, just a sunny brook-color; this is bordered at the sides by a line of iridescent blue-purple, while the shining silver scales on the sides below, flash and glimmer with the changing hues of the rainbow. The minnows are darker than the shiners; the horned dace develops little tubercles on the head during the breeding season, which are lost later.
The body of the shiner is ideal for slipping through the water. Seen from above it is a narrow wedge, rounded in front and tapering to a point behind; from the side, it is long, oval, lance-shaped. The scales are large and beautiful, the lateral line looks like a series of dots embroidered at the center of the diamond-shaped scales.
The dorsal fin is placed just back of the center of the body and is not very large; it is composed of soft rays, the first two being stiff and unbranched. The tail is long, large, graceful and deeply notched. The anal fin is almost as large as the dorsal. The ventral pair is placed on the lower side, opposite the dorsal fin; the pectorals are set at the lower margin of the body, just behind the gill openings. The shiner and its relatives use the pectoral fins to aid in swimming, and keep them constantly in motion when moving through the water. The ventrals are moved only now and then and evidently help in keeping the balance. When the fish moves rapidly forward, the dorsal fin is raised so that its front edge stands at right angles to the body and the ventral and anal fins are expanded to their fullest extent. But when the fish is lounging, the dorsal, anal and ventral fins are more or less closed, although the tip of the dorsal fin swings with every movement of the fish.
The eyes are large, the pupils being very large and black; the iris is pale yellow and shining; the whole eye is capable of much movement forward and back. The nostril is divided by a little projecting partition which looks like a tubercle. The mouth is at the front of the head; to see the capabilities of this mouth, watch the shiner yawn, if the water of the aquarium becomes stale. Poor fellow! He yawns just as we do in the effort to get more oxygen.
The shiners are essentially brook fish although they may be found in larger bodies of water. They lead a precarious existence, for the larger fish eat them in all their stages. They only hold their own by laying countless numbers of eggs. They feed on water insects and get even with their big fish enemies by eating their eggs. They are pretty and graceful little creatures and may be seen swimming up the current in the middle of the brook. They often occur in schools or flocks, especially when young.
Leading thought—The shiners are among the most common of the little fish in our small streams. They are beautiful in form and play an important part in the life of our streams.
Method—Place in the aquarium shiners and as many as possible of the other species of small fish found in our creeks and brooks. The aquarium should stand where the pupil may see it often. The following questions may be asked, giving the children plenty of time for the work of observation.
1. Do you know how the shiner differs in appearance from the minnow and chub and dace?
2. What is the shape of the shiner's body when seen from above? When seen from the side? Do you think that its shape fits it for moving rapidly through the water?
3. What is the coloring above? On the sides? Below?
4. Are the scales large and distinct, or very small? Can you see the lateral line? Where are the tiny holes, which make this line, placed in the scales?
5. Describe or sketch the fish, showing position, relative size and shape of all the fins and the tail.
6. Describe the use and movements of each of the fins when the fish is swimming.
7. Describe the eyes. Do they move?
8. Describe the nostrils. Do you think each one is double?
9. Does the mouth open upwards, downwards or forwards? Have you ever seen the shiner yawn? Why does it yawn? Why do you yawn?
10. Where do you find the shiners living? Do they haunt the middle of the stream or the edges? Do you ever see them in flocks or schools?