Coral World Underwater Observatory Eilat 2

The Red Sea Circular Exhibit is a 360 degrees exhibit in which the visitors stand in the middle and are surrounded by 360,000 litres of water featuring a complete natural ecosystem. The exhibit features corals, herbivore fish, carnivorous fish, parasites, crabs, shrimps and more, all living in one functioning ecosystem. All the animals are fed daily thus ensuring they don't harm each other. The Circular exhibit is used for research about the unique ecosystem of coral reefs. The water in the circular exhibit are pumped from 42 meters deep in the Red Sea and are circulated 24/7.

Source: https://en.wikipedia.org/wiki/Coral_World_Underwater_Observatory