Length: 4.5 - 5.0 mm
Beetles in the genus Laccophilus seem to eat primarily insect larvae, but they also scavenge bits of detritus from the pond bottom. Interestingly, three or four different species of Laccophilus may live in the same pond and even in the same part of that pond.
While you'll find them most often in the still waters of ponds and lakes, you may also see these beetles in streams.
American Insects site