costia vs flagellated protozoan

costia and flagellated protozoan both are nouns.

Word	Noun	Adjective	Verb	Adverb
costia	Yes	No	No	No
flagellated protozoan	Yes	No	No	No

As nouns, flagellated protozoan is a hypernym of costia; that is, flagellated protozoan is a word with a broader meaning than costia:

costia: a flagellate that is the cause of the frequently fatal fish disease costiasis
flagellated protozoan: a usually nonphotosynthetic free-living protozoan with whiplike appendages; some are pathogens of humans and other animals

Other hypernyms of costia include flagellate, flagellate protozoan, mastigophoran, mastigophore.

costia (noun)	flagellated protozoan (noun)
a flagellate that is the cause of the frequently fatal fish disease costiasis	a usually nonphotosynthetic free-living protozoan with whiplike appendages; some are pathogens of humans and other animals