Catfish have venomous spiny fins on them that pack a painful sting. The stings usually aren't serious however they can become infected. To avoid getting stung you should hold the catfish on the palm of your hand, on the ventral side of the fish. This allows you to place your fingers on either side of the pectoral spines, and are not coming in close contact with the dorsal spine. Keeping this grip avoids you getting stung.