I've always loved the show "River Monsters" because it confirmed to me that there were too many large fish out there.
Don't get me wrong, I'm glad they're thriving in their natural habitats, I just don't exactly want to go swimming with a six-foot-long alligator gar. One huge fish that I didn't know about is the giant trevally. They can grow up to five feet, and they're sometimes called "giant piranhas" despite the fact that they're completely unrelated. These giants are carnivorous, but they're pretty docile and won't harm humans. That doesn't mean you shouldn't be careful where you put your hands, as one man in the Cook Islands recently discovered.
Swimming in the water below the dock, first the travelers notice the school of giant trevally swimming beneath them.