During the winter months, the two large catfish species present in Minnesota behave differently. Channel catfish remain active and will congregate in loose schools in the rivers and lakes they inhabit. Anglers can target these fish through the ice [if ice is thick enough], or even in open water in deeper, slow-moving areas of rivers. The Horseshoe Chain of Lakes near Cold Spring is a popular destination for anglers looking to target channel catfish through the ice.
Flathead catfish, on the other hand, migrate to wintering areas when the water temperatures dip down to 50-55 degrees Fahrenheit. They congregate in deep holes in the rivers, out of the current, and essentially go dormant until the water warms in the spring. Many dozens of these large fish can stack up on top of one another in groups and are highly vulnerable to illegal snagging. A recent change in Minnesota fishing regulations has closed the angling season for flathead catfish from Dec. 1 to March 31 to protect these large, dormant fish from being over exploited.