English: Antler coral (Pocillapora grandis ) with blue damselfish (Pomacentrus pavo ) Moorea, French Polynesia. Antler coral can grow to more than a metre in diameter. Research has shown that the coral is more likely to grow if it hosts a colony of blue damselfish. The coral offers the damselfish protection; the larger the coral, the better the protection. Blue damselfish are known as ‘interference competitors’. They chase other fish away, including some species that eat coral. See here.