Had a days leave today, and went down to the local river with my 8 year old daughter. The water is actually only a few inches deep in many parts and the bottom stony with some smooth areas and also lots of loose stones. Ideal for bottom living fish and also freshwater mussels. Here are a couple of the fish we brought home for the aquarium and pond.

Bullhead or Miller's Thumb,
Cottus gobio
-about 3 inches in length. Loads of these about from baby ones to big grumpy old-timers (and doesn't he look grumpy!).

Stone loach
Nemacheilus barbatula
-about 5 inches in length