Ichthyomys

Ichthyomys is a genus of semiaquatic Neotropical rodents in the family Cricetidae. It contains the following species:
 * Crab-eating rat (Ichthyomys hydrobates)
 * Pittier's crab-eating rat (I. pittieri)
 * Stolzmann's crab-eating rat (I. stolzmanni)
 * Tweedy's crab-eating rat (I. tweedii)

Members of the genus tend to be nocturnal and live along fast-flowing streams, where they feed on freshwater invertebrates such as crabs.