In the aquarium hobby, stony corals are broken down into two categories, LPS (Large Polyp Stony) and SPS (Small Polyp Stony) corals. LPS are typically large calcareous corals with large fleshy polyps. Many LPS have long, flowing sweeper tentacles that sting and are used to keep other animals away from them. LPS corals are considered easier to keep in an aquarium and require less intense lighting and water currents than SPS. In order to thrive, LPS need excellent water quality and adequate calcium levels.