Flowerpot corals, despite their delicate names, are generally aggressive animals (3). They are capable of developing elongated 'sweeper' polyps, like the sweeper tentacles of other corals, which can inflict severe tissue damage on a coral within their reach. It is therefore unusual to see other coral species growing close to the flowerpot coral (3), and it is believed that this adaptation benefits the flowerpot coral in the intense competition for space on the reef (5). Like other reef-building corals, flowerpot coral polyps have microscopic algae (zooxanthellae) living within their tissues. Through photosynthesis, these symbiotic algae produce energy-rich molecules that the coral polyps can use as nutrition. In addition, the large polyps can use their tentacles to capture plankton to feed on, and thus are not as reliant on sunlight, required for photosynthesis, as some other coral species (4). Flowerpot corals have separate male and female colonies (not all corals do) which release sperm and eggs into the water for external fertilisation. The fertilised egg develops into a free-swimming larva that will eventually settle on the substrate and develop into new colonies (3).