Most species of catfish are not dangerous to humans. They are generally peaceful, bottom-dwelling fish that are not aggressive towards people. Catfish have venom on their dorsal, but they are not typically strong enough to cause harm to humans. However, some larger species of catfish, such as the Mekong giant catfish, can grow up to 10 feet long and weigh over 600 pounds. These fish may be capable of causing injury if they were to accidentally strike a person with their body or tail while swimming. It is best to exercise caution and avoid handling or trying to touch large catfish in the wild. (via Best Life Online).