Most canals will have Pike and Perch, Roach, maybe Carp, Bream, Rudd and the odd Tench. Never tried eating any of them but each to their own. I once heard this recipe for Pike which gives you some idea of its table quality:
Gut the Pike, cut off its fins.
Stuff the Pike with herbs, tarragon, dill, parsley
Cut two lemons in half and squeeze juice over pike. Put remaining lemons in with herbs
With butchers string tie the pike to a cedar plank that has been soaking in water for at least an hour
make sure your BBQ is at medium heat and put pike/plank in centre of BBQ over indirect heat
cook for an hour
Remove pike/plank from BBQ. Discard Pike and eat Plank.