1of5 Cactus Moths, an invasive species, feed of Prickly Pear cactus before metamorphosis.Dr. Larry GilbertShow MoreShow Less 2of5 Invasive zebra mussels put native fisheries at risk and can coat and clog water infrastructure, such as pipes, causing millions of dollars in damage. Courtesy Texas Parks and Wildlife DepartmentShow MoreShow Less 3of5 4of5 If you see this alien-like mollusk, be sure to not get too close.IllogicalMagic/RedditShow MoreShow Less 5of5 If you've spotted striped mussels on a weekend swimming trip or seen a Nerd's Rope-looking glob of pink matter along the River Walk, you've witnessed first hand the pressing problem of invasive species in San Antonio.