tropical prawn vs decapod

tropical prawn and decapod both are nouns.

Word	Noun	Adjective	Verb	Adverb
tropical prawn	Yes	No	No	No
decapod	Yes	No	No	No

As nouns, decapod is a hypernym of tropical prawn; that is, decapod is a word with a broader meaning than tropical prawn:

tropical prawn: edible tropical and warm-water prawn
decapod: crustaceans characteristically having five pairs of locomotor appendages each joined to a segment of the thorax

Other hypernyms of tropical prawn include decapod crustacean.

tropical prawn (noun)	decapod (noun)
edible tropical and warm-water prawn	crustaceans characteristically having five pairs of locomotor appendages each joined to a segment of the thorax
	cephalopods having eight short tentacles plus two long ones