Damselflies are also called dancers because they do not sit still for long. Damselfly nymphs are slender and have three gills on their rear. They are only about 0.8 inches long. They eat the same foods as dragonfly nymphs but smaller in size. They are less likely to go for fish and frogs, sticking instead to small insects and crustaceans.
Adults eat small insects.
There is a site with drawings of larval and adult damselflies at this water bug site .