In bony fish, what sensory system detects water movement along the body?

In bony fish, the lateral line system detects water movement along the body.

This sensory network consists of mechanoreceptors called neuromasts, usually arranged in canals or exposed grooves on the head and sides. Moving water bends tiny hair cells in the neuromasts, allowing a fish to sense nearby currents, vibrations, and pressure changes. The information helps with orientation, schooling, obstacle avoidance, and detecting predators or prey.

The lateral line is different from the ampullae of Lorenzini, which detect weak electric fields and are especially associated with sharks and rays. It is also not the same as hearing, although both systems respond to mechanical disturbances. Most fish have lateral lines, and the arrangement varies among species. In darkness or murky water, this system can provide an important map of the immediate surroundings.