The purposes of this study was to report on the status of the Round Goby, Neogobius melanostomu, in the Lake Erie watershed of Pennsylvania, to determine if there was a shift in diet of the native fishes when Round Goby were present in selected Pennsylvania tributaries of Lake Erie, and to compare the diet of the Tubenose Goby, Proterorhinus semilunaris, in Lake Erie with the native Iowa Darter. The relative abundance of the Round Goby in the Pennsylvania waters of Lake Erie, USA has increased dramatically since 1996. Associated with this increase, all benthic species, except Trout-perch Percopsis omiscomaycus in the lake decreased in occurrence or were absent. The Tubenose Goby which has established a reproducing population in Presque Isle Bay, Lake Erie, coexists with the Round Goby and Iowa Darter Etheostoma exile, a candidate species listed by the Pennsylvania Fish and Boat Commission. Conversely, the decline in potadromous populations of the Logperch, Percina caprodes, may be exacerbated by direct competition in the lake and the presence of Round Gobies in the breeding grounds of tributaries (e.g., Twentymile Creek). In Elk Creek, the presence of Round Goby is associated with dietary shifts of Rainbow Darters, Etheostoma caeruleum, although Rainbow Darters do co-exist with Round Goby. The Round Goby has now established a reproducing population in LeBoef Creek, a tributary of French Creek (Allegeheny River) and its presence documented in the main channel French Creek. It is suggested that reinforcing natural barriers (e.g., waterfalls) and enhancing population numbers of native species may be employed as management strategies to impede the spread of invasive species throughout the tributaries of Lake Erie.