Blackspot Emperor

This fish carries an Arabic name into the scientific literature. Working the 🌊 Red Sea coast in the 1760s, Peter Forsskal wrote down what fishermen there called it, Abu m'harrak, and when his notes were published after his death in 1775 the second word became the species name. Almost every animal in this catalogue is named in Latin or Greek. This one is named in the language spoken on the shore it came from.

The mark is a thumbprint: a large dark oval blotch on the flank just below the lateral line, one on each side, often rimmed with yellow. The rest is standard emperor. A long sloping forehead runs down to a pointed snout, the cheek carries no scales, the tail is reddish, and the thick-lipped mouth pushes forward when it feeds. Inside it are canines at the front for seizing and rows of blunt teeth behind for crushing.

That equipment is for a particular job. It works shallow sand, coral rubble, lagoon floors and seagrass, mostly at night, hunting animals that are already buried: worms, crabs, snails, brittle stars and small fish tucked into the sediment. Meanwhile the pattern is not fixed. The blotch fades and returns and the whole fish can go from pale to boldly barred fast enough that two photographs a minute apart look like two species.

It is one of the emperors a 🌊 Red Sea diver reliably meets, alone or in small groups over sand near the reef, usually in well under 20 m. Seagrass beds are the nursery. Adults hold home ranges whose size is settled by fights with their own kind, so the bigger the fish, the bigger the patch it keeps.

FishBase records 55 cm and 15 years, with 30 cm about ordinary; the regional guide gives 45 cm for this sea. Like most emperors it is thought to begin as a female and change to male. In Palau it has been recorded spawning in large aggregations during the first five days of each lunar month.