danube crayfish run on gravel substrate, carapace, eyes, legs animal at front glass, hornwort plant, european planted biotope

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