Bernhard from Vienna has put the photo with some control perches under "What is that?" and our admin Michael Limberger succeeded very quickly in the secure identification, it is Kyphosus ocyurus, which occurs in its native waters solitary, in schools, groups or shoals.
In schools of Kyphosus ocyurus, other control perches like Kyphosus elegans and Kyphosus vaigiensis are often observed.
The perch live predominantly near the surface (< 25 m) on rocky shores, in the open ocean and around reefs of isolated islands, but also in deep reefs, along walls and steep walls.
Kyphosus ocyurus eats almost everything that comes in front of their mouth.
With a size of up to 60cm no fish for a home aquarium, but certainly interesting for sport fisherman and fand also as a food fish.