UM, I am not an expert at all on this topic, but about gagged when you said to spray ANYTHING around the pond. My aunt had a Koi pond that had a canvas cover 8-9' up there. The spiders would climb the legs and put webs all over the place. So when my aunt had gone to the mall, Uncle sprayed for the spiders. Yup, when she came home, the Koi were all gasping for air and yup, they all died.