suckerfish vs spiny-finned fish

suckerfish and spiny-finned fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
suckerfish	Yes	No	No	No
spiny-finned fish	Yes	No	No	No

As nouns, spiny-finned fish is a hypernym of suckerfish; that is, spiny-finned fish is a word with a broader meaning than suckerfish:

suckerfish: marine fishes with a flattened elongated body and a sucking disk on the head for attaching to large fish or moving objects
spiny-finned fish: a teleost fish with fins that are supported by sharp inflexible rays

Other hypernyms of suckerfish include acanthopterygian.

suckerfish (noun)	spiny-finned fish (noun)
marine fishes with a flattened elongated body and a sucking disk on the head for attaching to large fish or moving objects	a teleost fish with fins that are supported by sharp inflexible rays