shoals

A sandbank or sandbar creating a shallow.

A shallow in a body of water.

To arrive at a shallow (or less deep) area.

To cause a shallowing; to come to a more shallow part of.

To become shallow.

Any large number of persons or things.

(collective) A large number of fish (or other sea creatures) of the same species swimming together.

To collect in a shoal; to throng.