What do anterior dorsal fins on bony fish?

* Stabilize the fish as it swims. The anterior dorsal fin helps to keep the fish from rolling over as it swims.

* Help the fish to turn. The anterior dorsal fin can be used to help the fish turn by providing resistance against the water.

* Protect the fish from predators. The anterior dorsal fin can be used as a defensive weapon against predators.

* Attract mates. In some species of bony fish, the anterior dorsal fin is used to attract mates.

* Provide camouflage. In some species of bony fish, the anterior dorsal fin is used to camouflage the fish from predators.