An aquatic plant called hydrilla is spreading across the surface of Canyon Lake. The Inland Fisheries Division of the Texas Parks and Wildlife Department says hydrilla first appeared in the lake in 2020. The plant is a prohibited exotic species, making it a crime to deliberately introduce it into any body of water in Texas. The low water level in the Guadalupe River enhances the growth of submerged aquatic plants, but so far hydrilla coverage hasn't exceeded ten-percent of Canyon Lake's surface area.