The fish get their name for their prominent barbels that resembles a cat’s whiskers. Despite their name, not all types have those prominent barbels. Catfish range in size and behavior from the longest and heaviest, Mekong giant catfish from South-east Asia, to species that eat dead material on the bottom. Even to a tiny parasitic species that lives in the amazon basin, and are known to swim up through the human urethra.
There are some types that are armor plated and some types that are naked. Neither of them have any scales.In some species; the mucus-covered skin is used in cutaneous respiration, where the fish breathes through its skin.
Catfish are nocturnal, meaning they are active during the night and sleep during the day. They therefore have highly developed senses. Most catfish are bottom feeders. In general, they are negatively buoyant, which means that they will usually sink rather than float due to a reduced gas bladder and a heavy, bony head.
Catfish have chemoreceptors across their entire bodies, which mean they “taste” anything they touch, and “smell” any chemicals in the water. Their barbels and chemoreceptors are more important in detecting food, since the eyes on catfish are generally small.
Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species are important in the aquarium hobby. However, these fish will bite and can damage objects in the aquarium. Due to both its aggressive and its predatory nature, this species should be kept alone.
Various species of catfish can be found inland or in coastal waters. They can inhabit freshwater or saltwater, many prefer shallow running water and some live underground. Some species inhabit caves.
Native to the Mekong area in Southeast Asia, with recorded sizes of up to 3.2 m and 300 kg, the Mekong giant catfish currently holds the Guinness Book of World Records for the world’s largest freshwater fish.
Thai and Laos anglers consider it a “spirit fish,” bringing good luck to those who catch them. The Giant Catfish has long been a great delicacy. Some years ago, Bangkok restaurants had to order the catfish one year in advance, and a small bowl of tom yam pla buak was priced at a minimum of 150 baht.
This catfish is in danger of extinction due to overfishing, as well as the decrease in water quality due to development and upstream damming, the species no longer inhabits the majority of its original habitat. Fishing for the Mekong giant catfish is illegal in the wild in Thailand, Laos, and Cambodia, but the bans appear to be ineffective, and the fish continue to be caught in all three countries.
Since the 1980’s, the Thai Fisheries Department has run a breeding program, and many are now stocked in reservoirs and private lakes. These fish have been released in some of the largest lakes in Thailand. The flooded valley which is Cheow Lan Lake in Khao Sok is one of the last places, where you have the chance to see one alive in the wild.