head, mouth and barbels of a juvenile dangerous invasive freshwater predator channel catfish, ictalurus punctatus hiding

aggressive america animal aquaculture aquarium aquatic barbel barbels biotic biotope cat catfish channel clear close coldwater dangerous dense ecology ecosystem european fauna fish freshwater greedy grey head hiding ictaluridae ictalurus instinct invasion invasive juvenile mouth natural nature popular predator punctatus reservoir river sand states system tank threat underwater united vegetation voracious water widespread wild