 Eric Partridge refers to these sporting terms as "snob plurals" and conjectures that they may have developed by analogy with the common English irregular plural animal words "deer", "sheep" and "trout".Similarly, nearly all kinds of fish have no separate plural form (though there are exceptions—such as rays, sharks or lampreys).As to the word "fish" itself, the plural is usually identical to the singular, although "fishes" is sometimes used, especially when meaning "species of fish".