Meet “Smack”. I think Smack is a male Yellow Box fish. https://en.m.wikipedia.org/wiki/Yellow_boxfish
But I’m not an expert and am happy to be corrected.
Every morning we hear a loud smack noise alongside our yacht and know that Smack is having breakfast. Some unsuspecting crustacean has become a tasty meal.
He’s quite an extrovert and swims to the surface when we stand on the swim deck or jump ashore.
His small mouth is deceptive, judging by the amount of green weed which he chomps off our lines in search of creatures.
I think he prefers the meaty bits to the green stuff.
He looks as though he’s whistling.
Smack has a buddy, a larger, shy fish, who disappears when rumbled . I’m not sure if it’s Mrs Smack.