Lake Placid is 'infested' with zebra mussels, also found at Medina Lake By Lauren Reid AUSTIN, Texas - Lake Placid is 'fully infested' with zebra mussels, according to the Texas Parks and Wildlife Department (TPWD). Infested status means that there is now evidence of an established, reproducing population of zebra mussels in the lake. TPWD also said zebra mussels had been detected at Medina Lake. The detection in Medina Lake, located near Bandera, marks the first introduction of invasive zebra mussels in the San Antonio River Basin. "Finding zebra mussels in a new river basin, unfortunately, means that they’ve most likely been transported there by boats, barges, or other equipment that didn’t take appropriate precautions to prevent their spread," said Monica McGarrity, TPWD Senior Scientist for Aquatic Invasive Species. "The vigilance of all boaters and anglers is needed to stop or slow the further spread of zebra mussels in Texas lakes."