sea creature vs marine animal

sea creature and marine animal both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea creature	Yes	No	No	No
marine animal	Yes	No	No	No

As nouns, sea creature and marine animal are synonyms defined as:

sea creature and marine animal: any of numerous animals inhabiting the sea including e.g. fishes and molluscs and many mammals

Other synonyms of sea creature include marine creature, sea animal.

sea creature (noun)	marine animal (noun)
any of numerous animals inhabiting the sea including e.g. fishes and molluscs and many mammals	any of numerous animals inhabiting the sea including e.g. fishes and molluscs and many mammals