The rainwater killifish (Lucania parva) is a small silvery fish with yellow flashes and diamond shaped scales that is widespread from Cape Cod, Massachusetts, through to Tampico, Mexico. It is commonly found in large numbers in fresh to brackish estuarine environments. A wholly unremarkable fish, it feeds on tiny crustaceans, mosquito larvae, small worms, and mollusks. Maximum size: 62 mm.