Summary and Conclusions Six species of fish, black bullhead (Ameiurus melas), black crappie (Pomoxis nigro-maculatus), large mouth bass (Huro salmoides), northern pike (Esox lucius), yellow perch (Perca flavescens), and rainbow trout (Salmo gairdnerii irideus) was injected intraperitoneally with 1 ml of a 48 hour culture of Pasteurella tularensis. All of the fish were negative from 1 to 10 days after inoculation as determined by guinea pig inoculation, serum agglutination tests, and attempts at direct cultural isolation of the organism. Bullheads fed infected liver also remained negative. These negative findings indicate that certain fish are not susceptible to tularemia and, consequently, would not represent a reservoir of the disease and a public health menace.