The Opossum Shrimp Mysis diluviana (formerly M. relicta, herein Mysis) is a small, shrimp-like crustacean native to cold, deep lakes in the Great Lakes region of the U.S. and Canada. Mysis were introduced to lakes and reservoirs to improve resources for sport fishes. Mysis had important effects on food webs, but few studies have examined the outcomes of the introductions in Colorado or the extent of potential invasions by natural dispersal...