narrow-clawed crayfish crawl on twig, gravel substrate in european planted biotope aquarium, captive domesticated

astacus leptodactylus danube crayfish turkish astacidae rostrum telson periopod antenna exoskeleton crustacean appendage decapod harmful nocturnal cultivation aquaculture underwater clearwater weed driftwood predator omnivore necrophage ecology threat unusual fauna aquadesign water wildlife temperate edible instinct behaviour wildcaught controlled conditions ecosystem habitat vegetation hardscape destructive space environment biodiversity fishkeeping hobby hornwort shallow dof bogwood coldwater camouflage