I have 2 of these Metal Marine portable livewells and love them, one is a 5 gallon and the other is a 20 gallon (I made the 20). In the 20 I've put 20-30 pin fish the night before going out fishing and they were all alive the next day. The one I made Ibought the pump at Academy and found an old 100lb chlorine bucket, put a door on top and put the pump in.
http://www.marinemetal.com/mmpweb5.html