Catfish are the most common of the freshwater catfish and can be easily identified because of their distinctive forked tails and dark spots scattered around the body. These fish are generally more slender and have a smaller heads than other catfish. Of course, catfish have the characteristic long barbels, commonly called feelers or whiskers, around the mouth that help them to locate food. The anal fin consists of 24 to 29 rays, further distinguishing it from other catfish.
Catfish come in many color variations with color depending on location and environmental conditions. One common coloring is gray or grayish-brown on top with dark brown and/or dark green dorsal fins. Others include pale blue and pale olive with a slightly silver tint. Side colors range from yellows to greens to white and there are even albino catfish that are white or cream colored with pink eyes. During spawning season, the dorsal area of the male may become completely black, dark blue, light blue, or silver.
Catfish seem to have unlimited growth potential and have been known to grow to more than 50 pounds. Their size range is smaller than the blue or flathead catfish but their populations are greater.
The casque is not, as sometimes stated, horny or bony or a protuberance from the skull but a tough keratinous skin covering a core of firm, cellular foam-like material (similar in structure to Styrofoam). It is longitudinally rigid but can be squeezed at the sides. Elastic and resilient, it acts as both shock absorber and as an indicator of age and dominance. The cassowary lowers its head when running and, in that position, the casque with its backwards-sloping inclination, serves to deflect vines/vegetation away from the head. It starts to develop in young birds 18 -24 months old.
Catfish can be found in all types of fresh water throughout the United States, southern Canada, and northeastern Mexico. Their numbers are greatest in the region running from the Appalachian Mountains west to the central part of the United States. Thanks to introduction programs, their numbers are increasing along both the east and west coasts.
Catfish will inhabit all bodies of fresh water -- streams, rivers, ponds, lakes, and reservoirs – and will thrive in nearly any type of water that provides adequate food, spawning and temperature. They will usually seek areas with clean bottoms of sand, rubble or gravel. This leads them to congregate in warm, quiet areas away from strong currents. In these areas, they will be found near dark holes and deep pools, lakeshores, undercut banks, rock ledges, weedy areas, log jams, and beaver dams or muskrat burrows.
Catfish are particular about their breeding habits. Beginning in late spring, males develop muscle pads on their heads and their bodies change color. Both males and females will seek out well-hidden places such as rock ledges, undercut banks, and hollow logs in which to build nests.
Male and female catfish engage in a period of courtship prior to spawning. Mating involves wrapping their tail around the head of the other. This stimulates the release of 5,000 to 20,000 eggs wrapped in a gold colored gelatin-like mass. Until they hatch in about six to 10 days, the male guards the nest against predators and cares for the eggs by fanning them with its tail to ensure adequate oxygen. The male may also eat a small number of the eggs during this time.
Catfish are omnivorous, which means they eat a wide variety of food items depending on what is available in their environment. They are most attracted to foods that have a strong odor and they have a strong sense of smell to guide them. The diet of the catfish is influenced by their size, their location, and the season.
Smaller catfish feed mostly on bottom-dwelling organisms such as insect larvae and invertebrates such as snails and clams. As they grow larger their diet changes to include a wider variety of food. Once a catfish is larger than 16 inches, live and dead fish become the main source of food. During winter months, especially where ice is present, they will eat mostly dead fish at the bottom of a lake or river. Throughout spring and summer, catfish will feast on an abundance of worms, fish, frogs, crayfish, insects, algae, and any other plant or animals that they find tasty. During the fall, fish and frogs become a larger part of their diet.