goldfish vs silverfish

goldfish and silverfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
goldfish	Yes	No	No	No
silverfish	Yes	No	No	No

As nouns, silverfish is a hyponym of goldfish; that is, silverfish is a word with a more specific, narrower meaning than goldfish:

goldfish: small golden or orange-red freshwater fishes of Eurasia used as pond or aquarium fishes
silverfish: a silvery variety of Carassius auratus

goldfish (noun)	silverfish (noun)
small golden or orange-red freshwater fishes of Eurasia used as pond or aquarium fishes	a silvery variety of Carassius auratus
	silver-grey wingless insect found in houses feeding on book bindings and starched clothing