I know everybody has been saying black bullhead but I have to disagree. I think it may be some sort of mad tom. Look at the tail. Now, maybe I'm wrong but in the second picture, if his tail isn't pinched and is fanned out as far as it goes, then, it isn't a bullhead.
The distinguishing feature of the madtoms are that the adipose and caudal fins are obviously connected. For these cats the adipose fin is free. The caudal fin shapes do look similar but without the key feature it doesn't matter.