Sea goldie fish (Pseudanthias squamipinnis) over a hard coral. This fish is found around coral reefs throughout the tropical Indo-Pacific region, from eastern Africa to the western Pacific. It forms large shoals around reef edges, feeding on zooplankton. Shoals are led by one dominant male, who is territorial and guards his harem of females. The sea goldie is a protogynous hermaphrodite: all the fish start life female, then when the dominant male dies the largest female turns into the new dominant male. Males are around twice the length of females, around 15 centimetres compared to seven. Photographed in the Egyptian Red Sea.