sand flea vs sandhopper

sand flea and sandhopper both are nouns.

Word	Noun	Adjective	Verb	Adverb
sand flea	Yes	No	No	No
sandhopper	Yes	No	No	No

As nouns, sand flea and sandhopper are synonyms defined as:

sand flea and sandhopper: small amphipod crustaceans that hop like fleas; common on ocean beaches

Other synonyms of sand flea include beach flea, sand hopper.

sand flea (noun)	sandhopper (noun)
small amphipod crustaceans that hop like fleas; common on ocean beaches	small amphipod crustaceans that hop like fleas; common on ocean beaches