I can tell you now what doesn't appeal to me about that job. I don't really like the idea of not being completely surrounded by breathable air (which is why I'll never be an astronaut). I don't really like to have lots of people looking at me; performance gives me hives. I know I wouldn't be putting on a show or anything, but I also know that as an aquarium visitor, I'm much more interested in the window-washer than the fish. I don't really like to swim, nor do I like wearing the things you need to wear in order to swim—they're uncomfortable to wear, uncomfortable to put on, even more uncomfortable to take off when they're wet, and then putting on dry clothes afterward is uncomfortable, too.
Oh, and fish are creepy.
Good think I never became a marine biologist, eh?