The color of the flathead catfish is dark to olive-brown with dark brownish mottlings on the sides, especially in the younger fishes. After inhabiting waters that flow over sand or light bottoms, adults are often light tan or even yellowish in color. The anal fin is very short with only 15 to 17 rays. The head is broad and flat, and the tail is square or very slightly notched. The jaws are heavy, and the lower mandible is longer than the upper.
The flathead catfish is a "big-water" species of fish, found quite commonly and widely distributed throughout the Great Border Rivers, in the large interior streams and in the flood control reservoirs (Coralville, Saylorville, Rathbun and Red Rock). Few specimens have been reported from the natural lakes and man-made lakes, but check the stocking records to see if Flathead Catfish have been stocked at your favorite lake.
They feed largely on insect larvae, crayfish, mollusks, fishes, worms, and terrestrial animals that wash into the streams.
81 pounds - Lake Ellis, Lucas County, June 1958 - Joe Baze, Chariton, Iowa
try fishing with small sunfish under cut banks after dark and don't forget to use strong hooks!
The Flathead Catfish can be found in most large interior streams of Iowa and is one the most abundant large catfishes of the Mississippi and Missouri Rivers. It is almost absent from the interior streams of the Missouri River basin and rare in natural lakes, man-made lakes and reservoirs.
The Flathead Catfish inhabits a wide variety of habitats and can tolerate extreme turbidity but avoids headwater creeks, high-gradient streams and strong currents. During the daylight hours it is typically found adjacent to deep pools created by strong current in large sluggish rivers, or low gradient tributaries of large streams. In Iowa and Illinois, the Flathead Catfish is found mainly in mud-bottomed areas and deep waters in pools. The Flathead Catfish also inhabits reservoirs, but is more plentiful below dams of major impoundments. It is usually found about drift piles, submerged logs or fallen trees with hard-bottomed substrates of sand or silt. Riffles are used nocturnally feeding adults and are the main habitat of young, which also stay in pools, backwaters and sheltered places as they mature.
Spawning occurs in June and July in secluded hides and obscure places. These fish are nest builders, and parent fish guard the eggs and young. The young reach a length of from 2 to 6 inches the first year and are sexually mature in the third or fourth year of life. Adults grow to enormous size. The state record fish, that weighed 81 pounds, was taken from Lake Ellis in Lucas County. Reports of huge flatheads of more than 100 pounds have been passed along through generation along the Mississippi River, but efforts to document their truth have been difficult and may be more river lore than factual.
Flathead Catfish are found principally in mud-bottomed areas and prefer deep waters in pools. They feed largely on insect larvae, crayfish, mollusks, fishes, worms, and terrestrial animals that wash into the streams. Small individuals, from 8 to 10 inches in length, have been observed feeding extensively on schools of young minnows in the shallow water. Large flatheads, those more than 20 inches in length, are almost wholly piscivorous in their feeding behavior, either taking fish alive or dead fish from the bottom.
Flathead Catfish are harvested by commercial fishermen from the Mississippi River. Approximately 85,000 pounds of Flathead Catfish valued at over $40,000 are annually harvested from the Mississippi.
Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.
Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.
Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames
Illustration by Maynard Reece, from Iowa Fish and Fishing