dytiscus marginalis big and terrible wide-spread freshwater predator insect in european coldwater biotope aqua

adult aggressive algae animal aqua aquarium background beetle behaviour big biotic biotope bug clear coldwater dangerous decorative display diving driftwood dytiscus eco ecological ecology endemic europe european fauna fish fishkeeping free fresh freshwater gravel great hornwort hunt hunter insect lake look macro male marginalis natural nature predator protection space tank temperate terrible underwater vegetation water weed widespread wild