cichlid vs percoid fish

cichlid and percoid fish both are nouns.

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

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

cichlid: freshwater fishes of tropical America and Africa and Asia similar to American sunfishes; some are food fishes; many small ones are popular in aquariums
percoid fish: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of cichlid include percoid, percoidean.

cichlid (noun)	percoid fish (noun)
freshwater fishes of tropical America and Africa and Asia similar to American sunfishes; some are food fishes; many small ones are popular in aquariums	any of numerous spiny-finned fishes of the order Perciformes