When people refer to "fish" are they strictly referring to ultra aggressive maniacs? I think there are a variety of fish that you can take advantage of:
Maniacs: If you have said "fish" covered, give them bad odds to draws and otherwise just play normal straightforward poker (no bluffing, no slow playing though c-bets are fine). If they have you covered, you're probably going to have to revert to playing very tight and if they get lucky, hey, this is poker we're talking about.
Weak tight players: Steal, steal, steal! You need to be able to identify these people and you need the ability to lay down good hands but once you can do this, your bubble play gets a whole lot better.