sand flea vs beach flea

sand flea and beach flea both are nouns.

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

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

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

Other synonyms of sand flea include sand hopper, sandhopper.

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