The Snake River fine-spotted cutthroat trout is a form of the cutthroat trout (Oncorhynchus clarkii) which is considered either as a separate subspecies Oncorhynchus clarkii behnkei, or as a variety of the Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri). The fish takes its common name from its original habitat, the Snake River of southern Idaho and western Wyoming, and from its unusual pattern of hundreds of small spots that cover most of its body, differing from the larger-spotted Yellowstone cutthroat pattern. Genetically it cannot be distinguished from the Yellowstone cutthroat trout, and before the construction of dams there were no physical barriers between the ranges of the two subspecies in the Snake river drainage.

Ref: Snake River fine-spotted cuttthroat throut