Common blue damselflies are very successful predators of smaller insects. Appearing to drift among vegetation alongside lakes, ponds and canals, these damselflies will snatch tiny flying insects such as gnats out of the air. Widespread across the northern hemisphere common blue damselflies can be found as far apart as North America and Mongolia.

Males are mostly blue; females can be yellowish with variable markings. During mating a pair of common blue damselflies will lock together in a mating wheel, flying over water in search of suitable places to lay eggs.