Noun | 1. | sea poacher - small slender fish (to 8 inches) with body covered by bony plates; chiefly of deeper northern Pacific waters scorpaenoid, scorpaenoid fish - fishes having the head armored with bony plates Agonidae, family Agonidae - poachers alligatorfish, Aspidophoroides monopterygius - small very elongate sea poachers |