Scattered on the reef you will find coral heads that have a school of small fish hovering above them. And when you get close they will hide among the branches of the coral. However, if you go keep a distance – or slowly move in and stay still. The fish will soon after move out into the water again.
There are several species having this behavior but the most common ones are the beautiful Lyretail anthias, the Half-and-half chromis – and in some places you will find many Blue-green chromis or Humbug dascyllus. But there are more species. And if you see .e.g. a more green colored fish with dark tail and yellow base at the pectoral fin it is probably the Arabian chromis which is also a fairly common species living in groups among the branches of corals.
The Lyretail anthias is a popular fish in private saltwater aquariums as it is beautiful, social and always very active. When you see them in the Red Sea, they often form very large groups around big coral heads/outcrops. As mentioned in the book, they start their life as females and live in harems with 5-10 female per male. If the male dies, one of the female will turn into a male. A fascinating trait that the Lyretail anthias shares with about 500 other fish species. – As males seem to only evolve when needed, then I cannot explain why you sometimes can find large groups of males together… – If you know how that can happen, please let me know.
The benefits of staying in a group? Read also the extra material on Schooling species
Have you wondered what juvenile fish that is “in disguise” on page 23? – it is a Bullethead parrotfish (page 14).