channel cat vs blue cat

channel cat and blue cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
channel cat	Yes	No	No	No
blue cat	Yes	No	No	No

As nouns, blue cat is a hyponym of channel cat; that is, blue cat is a word with a more specific, narrower meaning than channel cat:

Other hyponyms of channel cat include blue catfish, blue channel cat, blue channel catfish.

channel cat (noun)	blue cat (noun)
freshwater food fish common throughout central United States	a large catfish of the Mississippi valley