porcupine fish vs porcupinefish

porcupine fish and porcupinefish both are nouns.

Word	Noun	Adjective	Verb	Adverb
porcupine fish	Yes	No	No	No
porcupinefish	Yes	No	No	No

As nouns, porcupine fish and porcupinefish are synonyms defined as:

porcupine fish and porcupinefish: spines become erect when the body is inflated; worldwide in warm waters

Other synonyms of porcupine fish include Diodon hystrix.

porcupine fish (noun)	porcupinefish (noun)
spines become erect when the body is inflated; worldwide in warm waters	spines become erect when the body is inflated; worldwide in warm waters