Forest Preserve District of Cook County, Illinois
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Little Fish
Nature Bulletin No. 258-A   February 25, 1967
Forest Preserve District of Cook County
Richard B, Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation

It is still winter on our lakes, streams and ponds but the fish beneath the crust of ice already sense that spring is just around the corner. The males of some kinds are flashing bright new colors not seen in summer or autumn. Other males flaunt special pearly knobs, horns and other insignia that dwindle or drop off in the months to come. More often than not, he is one of those midgets that, when fully grown, is no bigger than a man' s finger, maybe as small as a paper match. In an aquarium many of these small species are as colorful and interesting as fancy tropical fish.

Because Illinois is not especially noted as a fishing state, people often doubt the statement that we have more kinds of freshwater fish than any other similar area on earth. However, of the two hundred or more species known in the state, about two-thirds are little fish too small to take an angler's hook.

The main causes for this bewildering variety are clear. First, we have an assortment of aquatic habitats from which almost any freshwater fish can find one to suit its taste. In addition, Illinois waters are fertile, like the Illinois soils which feed them, and produce rich crops of fish food. The state is well-watered by a network of streams that range from cold clear spring-fed brooks to the mile-wide silt-laden "Father of Waters", some sluggish, some swift, some deep, some shallow -- we have them all. Our standing waters include everything from Lake Michigan and the glacier-made Chain O'Lakes down to the broad bottomland lakes of the Illinois Valley and the cypress swamps near the Ohio River. Also, Illinois is geographically the "fish crossroads" of the continent. Its waterways connect with the Mississippi and St. Lawrence river systems reaching out to Canada and the Gulf, to the Rockies, the Alleghenies and the Great Smokies. It is supposed that, over the ages, Illinois has received fish recruits of many kinds from these far-flung places and has offered them suitable homes.

Many of our better-known larger fish have dwarf relatives. For example, carp and goldfish are the big brothers of our fifty-odd kinds of true minnows, shiners, chubs and daces. While some of these common "bait" fish are lacking in color, the mature males of others are brilliantly marked with crimson, pink, yellow, jet black, or iridescent with blue, green and gold.

The huge hundred-pound catfishes of the big rivers have several tiny relatives that hide among weeds or under stones and make fine aquarium pets. The active little Mad Tom is chestnut brown with three veins of inky black along each side, while the brindled stonecat is delicately marbled with light tan and velvety black. The strikingly banded pigmy sunfish and the gaudy orange-spotted sunfish are kin to our black basses, crappies and bluegills. Several other "half pints" are orphans as far as large relatives are concerned -- among them the top- minnows, the trout-perch, the pirate-perch and a dozen others, including the diminutive cave fish.

Of all these little ones, we prefer that score of aquatic comedians -- the darters that skitter along the bottom -- blood cousins of the wall-eyed pike and the yellow perch. Some crouch behind stones that check the rush of water in roaring torrents and some, like the Johnny darter, will live almost anywhere.

Small fry are not always minnows.

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