Aquarist for a Day - Jonathan visits the New England Aquarium as a volunteer aquarist for a day to learn what it takes to care for thousands of fish in dozens of exhibits, up to the massive 200,000 gallon Giant Ocean Tank (GOT). What he finds is an eye opener-it's not all fun and games. Maintaining an aquarium is serious work. But it does have its benefits, as Jonathan discovers while diving in the GOT and feeding the sharks. Mandarinfish - Even experienced divers rarely get to see the Mandarinfish, a colorful reef fish that is so shy, it only comes out of hiding for a half-hour a day. Jonathan travels to the south Pacific to film spawning Mandarinfish and witnesses an incredible secret ritual. World's Largest Fish - Jonathan travels to Holbox, Mexico in search of the massive whale shark-the world's largest fish. Reaching 50 feet long, these animals grow larger than a school bus, but they are completely harmless since they eat only plankton and small fish. Jonathan gets up close and personal to a mouth the size of a small car in his investigation to discover why so many whale sharks visit Holbox every summer.