Outside of bad tastes from algae, hang the live catfish by their head and cut off their tails to let them bleed out. Remove all dark colored flesh from the fillets, deep skinning (removing about 1/8"+ of the flesh near the skin), and zippering (split the fillet along the lateral line and remove 1/4" of the flesh each side) will greatly reduce off flavors.



"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." Stephen W. Hawking