The whale shark is a slow-moving filter feeding shark and the largest known extant fish species. The largest confirmed individual had a length of 12.65 metres and a weight of more than 21.5 metric tons, and there are unconfirmed reports of considerably larger whale sharks. The whale shark holds many records for sheer size in the animal kingdom, most notably being by far the largest living non-mammalian vertebrate, rivalling many of the largest dinosaurs in weight.
This video shows my awesome experience with this huge mammal.