Blue catfish are round in shape with a flat belly, as they age they frequently develop a distinct hump in front of the dorsal fin. Their anal fin is long and has a straight margin and 30-35 rays of equal length. Their color tends to be shades of blue-gray, although they can take on a silvery appearance. The belly typically fades toward white at the very bottom. Their skin is smooth with no scales and generally free of markings.
Most blues are not sexually mature before reaching 24 inches. They spawn in late spring/early summer when water temperatures reach 75°F. Blues are nesters and prefer cavities in drift piles, logs, undercut banks, rocks, or other such areas. When young these cats pursue a varied diet, but as it grows it tends to eat primarily fish. Blue catfish commonly grow upwards of 40 pounds and weights over 100 pounds have been record.
Blue Catfish in Texas
Ictalurus is Greek meaning "fish cat", and furcatus is Latin, meaning "forked", a reference to the species' forked tail fin. Blue catfish have a forked tail, and are sometimes very similar to channel catfish. However, only the Rio Grande population has dark spots on the back and sides. The number of rays in the anal fin is typically 30-35, and coloration is usually slate blue on the back, shading to white on the belly.
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. 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. Individuals larger than eight inches eat fish and large invertebrates. Blue catfish commonly attain weights of 20 to 40 pounds, and may reach weights well in excess of 100 pounds. It is reported that fish exceeding 350 pounds were landed from the Mississippi River during the late 1800's.
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.
The blue catfish is the largest freshwater sportfish in Texas. Where mature populations exist, 50-pounders are not unusual. Typically, the largest fish are caught by trotliners, some of whom have landed specimens in excess of 115 pounds. The Texas rod-and-reel record is 121.5 pounds. Catfish is the second most preferred group of fish among licensed Texas anglers, and blues rank third behind channel and flathead catfish. Like the channel cat, the blue catfish is considered an excellent food fish.
Courtesy of Texas Parks and Game