The Sheepshead Minnow (Cyprinodon variegatus) is a small fish (to 75 mm), with a wide range in western Atlantic coastal waters, from Massachusetts to northern Mexico. It enters low-salinity and tidal fresh waters, and has become established in mineral-rich waters fresh waters in the southwestern US, as introductions with discarded bait. These introduced populations are a threat to native species of Cyprinodon spp. (pupfishes) in southwestern springs and streams. One puzzling introduction is the capture of 28 C. variegatus in the estuary of the Dungeness River, Wasshington, a tributary of the Strait of Juan de Fuca in 1949, with no further records. Possible vectors are an aquarium release or an unofficial release of Eastern Oysters (Greenfield and Grinds 1965; USGS Nonindigenous Aquatic Species Database 2024).