Zeke

A very angry young man with trouble trusting anyone. Zeke hasn't been ostracized so much as he has driven away potential friends through his brusque nature and refusal to open up.

He was not born a mermaid - this Happens to him sometime in highschool and isn't linked to his paralysis. This kickstarts his interest in swimming in general, so he learns how to make it work for him in human form as well and ends up joining his school's competitive team.

Zeke is fiercely independent and blows up extremely easily. It's frustrating to him that he has nobody in his life outside of family, but he's still too young and oblivious to his own behavior for him to realize it's his own fault, so he blames everyone around him for it instead.