Barred silver fish in a loose school above a reef edge, with black bands running along both tail lobes - the mark that names it and separates it from the other sergeants here.
Most of the time they are plankton feeders, facing into the current in open water. Then the males go to the bottom and change.
A breeding male takes a patch of hard substrate, cleans it to bare rock, and turns dark blue-gray all over - a color so different from the school above that divers routinely report it as another species. He courts passing females with loops and dips, several may lay on his patch, and he ends up guarding a purple carpet of eggs from every direction at once. He fans them, eats the dead ones, and attacks fish many times his size, including divers who get too close.
The eggs hatch in a few days and the male goes back to being a silver fish in a school. Nineteen centimeters (7.5 in), and one of the few reef fish whose entire appearance depends on what it is doing that week.
The genus. Abudefduf Forsskål 1775 - def (side). ETYFish
The species. Abudefduf sexfasciatus (Lacepède 1801) - sex (six) + fasciatus (banded). ETYFish
- silver-white body with five black bars and black bands along the tail lobes
- the tail bands are the field mark - the sergeant without them is a different species
- in loose schools above the reef, feeding in midwater
- length up to 19 cm
Why it's threatened
This species is potentially threatened by exploitation for the aquarium trade.
Threat classification from the IUCN Red List.
