Keiko

Keiko, the orca whale, was the iconic animal protagonist of the movie Free Willy. Even though being the most unlikely candidate for release because of his long years in captivity, Keiko became the first and only captive orca to be successfully rehabilitated and released back into the wild, where he thrived for over 5 years in his home waters, gaining over 1 ton during his rehabilitation, mixing it up with wild orcas, swimming across the North Atlantic, and finally passing as a middle aged orca.