The easiest way to understand catfish location in rivers is to look at small streams. Small streams are easier to get to know because the catfish's world is compressed into a small area. In a large river, major holes may be half a mile apart. On a small stream, however, half a mile might contain 10 holes.

You can move and see lots of water. More importantly, the continuing combination of riffles, holes, and runs, and the cover elements that may exist in them are obvious. Small rivers offer the quickest education in river anatomy and how catfish relate to it.

Riffles form when a river washes over a hard bottom. A pool of water builds at the head of a riffle, eventually ovrflowing and pushing over the constricted area like water forced through the nozzle of a hose. The force of current flowing against the softer substrate at the end of a riffle scours a hole. Holes are the home of catfish.

The depth of a hole varies according to current velocity and the size of the river, but all holes are deeper and wider than riffle and run areas in the same section of stream. Holes gradually become shallower at their downstream end as current slows and suspended materials settle to the river bottom. The tail end of a hole becomes a run-a river flat. Catfish often move upstream to smaller water during spring and early summer, then back downstream into bigger water during late summer and early fall.

During winter, catfish must gather in holes with sufficient depth, current, and oxygen to sustain them throughout the cold-water period. Such holes are most likely in downriver sections. Flatheads rarely move more than one tributary away from a major river, while channel cats may move into tiny creeks several tributaries removed from a major river. Blue cats, even more than flatheads, are fish of big rivers. Smaller blues may push upriver into the beginning stretches of tributary streams, but the biggest blues usually stay in big water.