User blog comment:Woohoot/The potential of Fishmen/@comment-3345720-20150708154150/@comment-4311127-20150710002250

They'd most likely be able to breathe underwater after eating a Devil Fruit. It'll just be a slow death if they ever do drown.

The fishman that travel the world likely know Fishman Karate are some other style to defend themselves. With Fishman Karate, CoA wouldn't be all that useful for them.