The Seaviates are creatures that Dr. Luther Paradigm has gene-slammed. You could argue that the Seaviates are sea creatures that were gene-slammed with human DNA, but the deciding factor on what was and was not a Seaviate came from Repteel, who was formerly a human, and is repeatedly referred to as a Seaviate.
Note 1: Moby Lick is listed here as he was mutated as a Seaviate before he broke his mind-control.
Note 2: El Swordo is listed here because although he never WAS under Paradigm's control, an attempt WAS made to create him as such.
Note 3: In season three, episode thirteen, Jab is seaviated - temporarily.