Brad is a merman who appears in Season 2, Episode 3 "Mermaid". He is the boyfriend and later spouse of Feejee.
In the episode, he arrives just before Puss proclaims his wedding vow to Feejee, and demands that the wedding be stopped. He crawls toward Feejee and the two embrace, and he tells everyone that he never thought Feejee would ever find another man to make him jealous, swatting away Puss with his tail when he protests about her forcing him to marry her being all a ruse.
He proposes to Feejee and she accepts, and the two kiss (much to the townspeople's disgust). They then slither and flop away together, as Puss looks on and tells them he may visit sometime.