These slow moving fish are not at all intimidated by divers, and often come to “greet” you on your dive. There are five species living in warm waters throughout the Indo-Pacific, although not all species are represented in all areas. In the Red Sea, for example, you will see just three species: longfin spadefish (Platax teira), circular spadefish (P. orbicularis) and golden spadefish (P. boersii).
Young spadefish look different to the mature fish. They have short bodies (nose to tail) compared to the size of their large dorsal and ventral fins. The brown juveniles of the circular spadefish, P. orbicularis, float sideways in the water and look very like drifting dead leaves. Those of the dusky spadefish (P. pinnatus), though, look like toxic flatworms.
All the juveniles prefer shallow, sheltered water such as in lagoons and among mangroves. You find the adults in deeper water on reefs and wrecks down to 20 or 30 m.
Previously spadefish were known as batfish, and many divers, myself included, still routinely call them this. They all have thin deep bodies. Other features they have in common are their greyish colouring and the two black or grey stripes going vertically down their bodies, one through the eye and the other at the back of the head.
Spadefish grow to between 45 and 60 cm long. With small mouths and teeth they specialise in eating algae and small invertebrates. Some even follow turtles and eat their poo.
Phylum: Chordata > Class: Actinopteri > Order: Acanthuriformes > Family: Ephippidae > Genus: Platax
References
Red Sea Reef Guide, Ewald Lieske and Robert Myers