I never catch any big ones, but I do catch tench when I wouldn't really expect to. When I lived in Manchester I got just two bites on a trip to the Leigh Canal - two tench. I walked half a mile to a famous barbel swim on the Derwent at Borrowash and on legered pellet had one bite - a tench. Last year I trotted a little float down a weirpool, sitting on the weir of a tiny stream, and the fish went, chub, dace.... tench.