The problem is, Pat, as we've seen from some posts recently, that fish that Brits think of as common (eg plaice) are not so well known on t'other side of the Atlantic, and vice versa. I wouldn't know what a shad looked like if it jumped up and bit me on the ankle. To me it's a fish that inhabits crossword puzzles and word games. Mind you, I'm not really sure what a dace looks like either, nor a tench.
MK