This slender, elongated catfish has a deeply forked caudal fin and a protruding upper jaw. Adult channel cats are dark gray along the back, grading to light yellow or greenish yellow along the sides, and white on the venter. Juveniles are typically light gray on the back and silvery on the sides and venter. The sides of juveniles and adults have scattered dark spots. The head profile of the channel cat is curved from the dorsal fin to the snout. The same dimension in the blue cat is straight, giving the head of this similar species a wedge-shaped appearance. Small adult channel catfish are confused with blue catfish but are distinguishable by the above characteristics plus anal fin morphology. This fin on the channel catfish has a rounded margin and 24 to 29 soft rays, while on the blue catfish the free margin is straight and rays number 30 or more. The pectoral spine has well-developed serrae on the posterior edge.

Flathead catfish (Pylodictis olivaris)

The flathead catfish is recognized by its head, which is flattened between the eyes, a projecting lower jaw, and recurved tooth patches on either side of the upper jaw. The back and sides of the body and fins are mottled with black, white, olive, and even pale yellow, with the venter white or pale yellow. The short, rounded anal fin contains 14 to 18 rays. The caudal fin is slightly notched, and the top of the upper lobe is white on all but extremely large individuals.

The long, sharp spines on the front edges of a catfish’s dorsal fins are connected to venomous glands. Although the spines can tear skin, the glands excrete venom. The venom is irritating and some people have had serious problems with infection afterward.

Blue catfish (Ictalurus furatus)

The blue catfish is recognized by a deeply forked tail and white chin barbels. The upper and lower jaws meet evenly, or the upper jaw may project slightly beyond the lower jaw. The anal fin on the blue catfish has 30 or more soft rays, and its free margin is straight. The anal fin on the channel catfish has 24 to 29 soft rays, and its free margin is rounded. In body color, the blue catfish is light blue, while the channel catfish is light yellow with small, scattered dark spots.

Distribution

Channel catfish are native to North America east of the Rockies from southern Canada, south into northeastern Mexico, and east of the Appalachians with the exception of much of the coastal plain north of Florida. The species has been widely introduced in other areas as far west as California.

Flathead catfish range from the lower Great Lakes through the Mississippi River watershed to the Gulf states.

Blue catfish are native to major rivers of the Ohio, Missouri, and Mississippi river basins. The range also extends south through Texas, Mexico, and into northern Guatemala.

Behavior

Channel catfish begin spawning in May, with fisheries scientists documenting the species continuing to spawn through August.

Flathead catfish spawning season is from late May through August, when the water temperature is between 75° and 80° F. Males select hollow logs, caves or areas beneath the banks for their nest sites. Males may even improve their selected sites by creating shallow depressions for the females to lay their eggs. Egg number varies greatly depending on female size, but the average is up to 100,000 eggs at a time. Scientists estimate that a female will lay 1,200 eggs for every pound she weighs. A female flathead that weights 50 pounds might release 60,000 eggs at a time. Males defend their nest and eggs aggressively. They will fan the nest with their tails to keep the eggs clean and provide them with oxygenated water. If females have been eating poorly, their bodies may conserve resources by not releasing eggs. Poor overall health and certain environmental conditions such as drought or flood can reduce flatheads' ability to spawn. In healthy times, clutches can reach 100,000 eggs, but only a small number will survive.

The spawning behavior of blue catfish appears to be similar to that of channel catfish. However, most blue catfish are not sexually mature until they reach about 24 inches in length.

Diet

Channel catfish feed on aquatic insect larvae, crayfish, mollusks, and small fish.

Flathead catfish prey only on live fish, unlike other catfish which are scavengers. Young flathead catfish feed mostly on invertebrates such as worms, insects and crayfish. When 10 inches or larger, their diet consists entirely of species such as shad, carp, suckers, sunfish, largemouth bass and other catfish (including their own kind).

Like channel catfish, the blue catfish pursues a varied diet, but it tends to eat fish earlier in life. Although invertebrates still comprise the major portion of the diet, blue catfish as small as four inches in length have been known to consume fish.

Habitat

Channel catfish inhabit rivers, reservoirs, small to large streams, backwaters, swamps, and oxbow lakes. They are common in varying conditions ranging from slow to moderate currents over sand, gravel, and silt and around submerged trees and aquatic vegetation.

Flathead catfish prefer deep pools of streams, rivers, canals, lakes and reservoirs, where the water is turbid (cloudy) and the currents are slow. Ideally, they seek shelter beneath rocks, roots and other cover and begin their independent lives, following their juvenile period shortly after spawning. Adults are usually solitary, each staking out a favorite spot under a tree or in a cove, in deep water. At night, they move into shallow areas to feed.

Blue catfish are primarily large-river fish, occurring in main channels, tributaries, and impoundments of major river systems. They tend to move upstream in the summer in search of cooler temperatures, and downstream in the winter in order to find warmer water.