While cockroaches are considered non-predatory or non-aggressive insects, different species of water bugs are often highly predatory, feeding on such quarries as small fish and tadpoles. Most species of water bugs are also dramatically larger in size than common cockroaches.
While water bugs often feast on living things, cockroaches usually prefer inanimate matter for nourishment, including plant material, leather, glue, rotting baked goods or dried skin flakes. In some instances, cockroaches do cannibalize wounded or dead members of their own species. Cockroaches are generally drawn to humid sites, collecting in warm and moist corners, whereas water bugs prefer wet or aquatic areas. This makes properties with standing water particularly susceptible to infestation by the latter.
Water bugs tend to lay their eggs in aquatic environments, particularly on floating vegetation or other forms of debris. Alternatively, cockroaches produce egg cases that they can either carry with them or deposit in protected nooks and crannies. While cockroaches are known to possess painful bites capable of hurting humans, they tend not to use them. However, despite this common passivity, cockroaches can still spread human diseases and are also known to trigger or exacerbate allergy symptoms and asthmatic conditions. Water bugs do bite people, but typically only when their environment is breached.