alligatorfish vs sea poacher

alligatorfish and sea poacher both are nouns.

Word	Noun	Adjective	Verb	Adverb
alligatorfish	Yes	No	No	No
sea poacher	Yes	No	No	No

As nouns, sea poacher is a hypernym of alligatorfish; that is, sea poacher is a word with a broader meaning than alligatorfish:

alligatorfish: small very elongate sea poachers
sea poacher: small slender fish (to 8 inches) with body covered by bony plates; chiefly of deeper northern Pacific waters

Other hypernyms of alligatorfish include poacher, sea poker.

alligatorfish (noun)	sea poacher (noun)
small very elongate sea poachers	small slender fish (to 8 inches) with body covered by bony plates; chiefly of deeper northern Pacific waters