scorpion fish vs scorpionfish

scorpion fish and scorpionfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
scorpion fish	Yes	No	No	No
scorpionfish	Yes	No	No	No

As nouns, scorpion fish and scorpionfish are synonyms defined as:

scorpion fish and scorpionfish: marine fishes having a tapering body with an armored head and venomous spines

Other synonyms of scorpion fish include sea scorpion.

scorpion fish (noun)	scorpionfish (noun)
marine fishes having a tapering body with an armored head and venomous spines	marine fishes having a tapering body with an armored head and venomous spines