The crew go about tossing the dead bodies overboard (giving their fallen comrade a small ceremony with a quiet prayer to one of their gods) and swabbing the deck, washing the blood away before it gets time to settle on the deck. They work quickly and efficiently, and soon there's nary a trace of the deadly combat that happened a little while ago. The sailors aren't particularly interested in the few items the fishmen carried, and will throw them overboard unless you grab it first.
After everything is done, the sailors settle back in for the night (with 2 lookouts this time) and things go quiet, except for the occasional snore.
The regular fish-men had normal tridents, the armored fish-man had a superior trident + Mitran holy symbol. What, if any, do you keep.