Darwin Raglan Caspian Ahab Poseidon Nicodemus Watterson III or simply Darwin Watterson is one of the main characters of the Amazing World of Gumball animated series. He used to be Gumball's pet goldfish, but grew two long legs, and two short arms and adapted to live outside of water. Darwin apparently has thick coatings of blubber that make him resistant to pain as he shows us in The Responsible episode. But Darwin is an optimistic and happy person. Truing to see the best in all scenarios and always keeps a smile on his face. A fanart Gumball progress bar for YouTube with Darwin walking.