are sheep for sheep and fish or fishes for fish. Sheeps is only a form of a verb. Sheeps means grazes. Yes, the plural of "whim" is boring old "whims." However,there is "cacti" and "cactuses." Even more fun is that there is "octopi," "octopuses," and "octopodes." More plurals fun: rhinoceroses, rhinoceri, rhinocerotes.