Larvae make silk nests under the leaves. It takes about 10 months for an egg to result in an adult. Eggs and larvae can be wiped off leaves. If the infestation is bad, plants can be treated with insecticides outside of the pond and returned after a good rinsing. Remove dead vegetation around the pond to reduce the population of overwintering adults.
Adults are a quarter to half an inch long.
Adults grow up to 1.5 inches depending on species while some larvae can grow to 3 inches. There are at least 500 species in North America alone. The larvae are called water tigers and have sharp pincers to eat tadpoles, their siblings, and other critters. Adults eat bugs, fish, tadpoles, each other, and frogs. They bring air bubbles underwater with them to breathe.