Final answer:
Reef fish, such as the Moorish idol, belong to Class Osteichthyes, which consists of bony fishes. They have a bony skeleton and are part of the subclass Actinopterygii.
Step-by-step explanation:
Reef fish, specifically the Moorish idol, belong to Class Osteichthyes which consists of bony fishes. The moorish idol is a type of reef fish that has a bony skeleton, paired fins, and belongs to the subclass Actinopterygii (ray-finned fishes). This class of fish is the most diverse and includes species like the sockeye salmon and coelacanth.