In Chongqing Joy Sea World in southwestern China, breeders put blocks of ice containing food into the water, allowing the park's sharks and other fish to enjoy a frozen treat. Iced cabbages were put into the water by visitors to feed the turtles. Experts say the frozen food’s main purpose is to decrease the marine animals’ body temperature. The original ocean temperature is between 17 and 20 degrees Celsius. The marine aquarium’s indoor temperature is around 20 degrees Celsius. Therefore the aquarium workers usually put lots of ice into the water to keep the temperature down. In hot weather the marine animals are often restless and fidgety. The zoo also adds a heatstroke-preventing medicine to the food to help put marine animals further at ease.