Well, this experiance is not exactly what you had in mind, but its close.
I am a dive master in the Padi system, and being in northern Tennessee, there just are not a lot of places to dive. When we are training new divers, we used to go to a rock quary in Kentucky called Curielian Springs.
In the protected area (no fishing), there were seriously catfish bigger than myself (6 foot 2, 230) and Largemouth and small mouth bass longer than my arms. The bluegill and brim were MONSTERS.
Now, it is a real change when the fish start coming up to nibble on you! Most of the experianced divers wore hoods, not to stay warm, but to keep our ears from being lures. The funniest thing was when a bass tried to eat a regulator from somoenes mouth, and hit the purge button. It seriously blew up like a balloon. When it spit it out, the whole fish rocketed back as the air escaped its system. Seemed to be fine, but needless to say we all lost it