Nautilus is fairly deep sea dweller, usually found at depths of around 300m - 500m. Their habitat will be the steep slopes of coral reefs such as the Great Barrier Reef. Feeding is a night time affair, when the Nautilus will rise to somewhere nearer to 100m depth to feed on the nightly migration of shrimp which also rise to more shallow depths to feed. They will also feed on small fish and crabs and other crustaceans and will take carrion. As their eyesight is rather poor, food is located by their keen sense of smell and captured in the tentacles, which can number up to 90.