Middle and hind tibiae are not flattened but equiped with a fringe of swimming hairs. The legs move alternately in contrast to predacious diving water beetles or most whirligig beetles. The English name of the group refers to their habit of crawling along different water plants. Larvae are mostly found among masses of algae. They move slowly and are very easily overlooked in their preferred habitat.
Haliplid larvae suck the contents of single cells of algae with their highly specialized mandibles.
They breathe by means of dorsal tracheal gills or microtracheal gills. Most species are testaceous with more or less distinct rows of black punctures on the elytra. The eyes are distinctly protruding. The 11-segmented antennae are devoid of pubescence and filiform. The prosternal process is broadened, truncate apically and adjacent with the metasternal process posteriorly.