goby vs percoid fish

goby and percoid fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
goby	Yes	No	No	No
percoid fish	Yes	No	No	No

As nouns, percoid fish is a hypernym of goby; that is, percoid fish is a word with a broader meaning than goby:

goby: small spiny-finned fish of coastal or brackish waters having a large head and elongated tapering body having the ventral fins modified as a sucker
percoid fish: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of goby include percoid, percoidean.

goby (noun)	percoid fish (noun)
small spiny-finned fish of coastal or brackish waters having a large head and elongated tapering body having the ventral fins modified as a sucker	any of numerous spiny-finned fishes of the order Perciformes