In the UK a Bullhead, is also known as a Miller's Thumb because of their shape, and the current record for this species stands at 1 ounce!! They have nasty spines which can cause infection if you get pricked by them.
We have only one species of Catfish here, and that is the European Catfish or Wels, See here
it is an introduced species in Britain, having been brought over from the european mainland.
Giok