It's basically an offshoot of a saltwater fish called the sheepshead minnow. It is only found in Lake County's Harris Chain of Lakes and Lake Weir in Marion County. State fisheries biologists say the pupfish was stranded here when the ocean that covered Florida receded eons ago. This small, 1- to 2-inch minnow is silver with darker vertical bands and prefers areas with a clean, sandy bottom. Sometimes, it burrows into the sand, with only its eyes exposed. A member of the killifish family, it eats small insects and mosquito larvae. Florida considers it a species of special concern because of its limited range.