animal group vs shoal

animal group and shoal both are nouns.

Word	Noun	Adjective	Verb	Adverb
animal group	Yes	No	No	No
shoal	Yes	No	Yes	No

As nouns, shoal is a hyponym of animal group; that is, shoal is a word with a more specific, narrower meaning than animal group:

Other hyponyms of animal group include team, brood, flock, flock, fold, herd, herd, pack, pod, pride, clowder, school, caste, colony, warren, breed, stock, strain, drove, litter.

animal group (noun)	shoal (noun)
a group of animals	a large group of fish
	a stretch of shallow water
	a sandbank in a stretch of water that is visible at low tide

animal group (verb)	shoal (verb)
	become shallow
	make shallow