A Shoal of Minnows
A group of minnows is called a shoal.
Jesse Gaggle
A Run of Salmon
A group of salmon is called a run — the mass upstream migration from ocean to freshwater spawning grounds.
A Glint of Goldfish
A group of goldfish is called a glint.
A Cluster of Porcupine Fish
A group of porcupine fish is called a cluster.
A School of Butterfly Fish
A group of butterfly fish is called a school.