Once again, Burgers' Ocean is donating a large batch of self-bred coral and fish to a fellow European public aquarium. On 15 July 2020, 39 stony corals, 40 soft corals and 15 fish will be sent to Tierpark Berlin. Due to its high success rate in recent years, the Arnhem coral reef aquarium has become Europe's leading supplier of self-grown coral. Since 2010, Royal Burgers' Zoo has shipped 2575 stony and soft corals.
On 5 November 2019, more than 100 self-grown coral colonies were transported from Arnhem to Düsseldorf (Germany) and Pula (Croatia). On 23 January 2019, Burgers' Zoo made national news with the transport of over 300 self-bred corals, sea anemones and coral fish to the London Aquarium and Chester Zoo (England). On 25 November 2010, 250 fish and corals travelled from Arnhem to four Danish aquariums. Since 2010, a total of 2575 corals bred in Burgers' Ocean have been donated to European counterparts: 1430 stony corals and 1145 soft corals. Corals are protected and are struggling in nature; mainly due to climate change, but also due to pollution and overfishing.
Burgers' Ocean is a tropical coral reef aquarium that holds eight million litres of water. The living coral reef in a 750,000-litre basin is a key part of the aquarium. The Arnhem zoo's living coral reef is the largest of all public aquariums in Europe. There are only two larger living coral reefs in aquariums worldwide: Townsville (Australia) and San Francisco (USA).
Corals can be divided into two main groups: soft corals without an exoskeleton, and stony corals that build a limestone skeleton, forming the base of a coral reef. The team of biologists and zookeepers at Burgers' Ocean has been successfully breeding soft and rocky corals for years. In the Ocean's earlier years, many corals were bred behind the scenes. Today, only a few very sensitive species are bred behind the scenes. After many years of diligent work, Burgers' Ocean's biologists and zookeepers managed to create a well-growing miniature coral reef in public view. It grows so fast that many corals have to be harvested regularly for fellow aquariums.
When corals grow against each other, they become hostile. They fight, using special long tentacles that contain poison. Some species expel their mesenterial filaments—their guts—onto a neighbouring coral to digest it. Corals also grow over each other, blocking the bottom coral from the light, which kills it. Yet other species produce a toxic substance which they release to poison other corals in the direct vicinity. To keep things under control, diving zookeepers regularly "prune" the reef to prevent the corals from growing too close to each other. The coral growth is extremely successful, resulting in a lot of pruning. All the pruned corals are donated to other public aquariums.