Angler For Ever

Though often used interchangeably, these words actually mean different things. Fish is used either as singular noun or to describe a group of specimens from a single species. Fishes describes a group containing more than one species.^[2] Hence, as plurals, these words could be used thus:

Main article: Shoaling and schooling

These goldband fusiliers are schooling because their swimming is synchronised

A random assemblage of fishes merely using some localised resource such as food or nesting sites is known simply as an aggregation. When fish come together in an interactive, social grouping, then they may be forming either a shoal or a school depending on the degree of organisation. A shoal is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. Schools of fish are much more tightly organised, synchronising their swimming so that all fish move at the same speed and in the same direction. Shoaling and schooling behaviour is believed to provide a variety of advantages.^[63]

Examples:

While school and shoal have different meanings within biology, they are often treated as synonyms by non-specialists, with speakers of British English using "shoal" to describe any grouping of fish, while speakers of American English often using "school" just as loosely.