there are many juvenile channels that dont have any spots. His location is FL so that already elimates anything with a forked tail but channel cats. Bullheads and madtoms have rounded tail fins.
Correction: I do believe them to be white cats... to the post above, there are no white bullheads. These are simply called white catfish. They are also not as common as some of the other types of cats. I would leave them there if there is any way that they can escape.