Adjective: bearing some physical and/or behavioral resemblance of a fish.
My
brother was making some
goofy faces at the dinner
table, and I described him as pescatine, not knowing it's not a word.
She stood there opening and closing her
mouth in a pescatine manner, searching for a suitable response.
"Oh, don't
mind him, his mind just flits about in a pescatine
way."