Naucoridae is a small family of insects commonly known as the creeping water bugs and saucer bugs. They are similar in appearance and behavior to Belostomatidae (giant water bugs), but considerably smaller, at 0.5–2 cm (0.2–0.8 in) long. Naucoridae are found around the world, but the greatest diversity is in tropical regions. They inhabit a wide range of freshwater habitats, ranging from still waters like ponds, to flowing rivers and even torrential streams. There are about 400 species in 40 genera in 5 subfamilies.