Which archerfish species can distinguish between different human faces in studies?

The archerfish species shown to distinguish between different human faces in studies is Toxotes chatareus.

This fish is better known for shooting a jet of water at insects above the surface, but its visual abilities are unusually sophisticated. In laboratory experiments, T. chatareus learned to discriminate among projected human faces, demonstrating that a fish without a mammalian neocortex can classify complex visual patterns.

The finding does not mean the fish recognizes people in the same social way humans recognize friends. The experiments tested visual discrimination: the archerfish learned that particular face images were associated with a target or reward and could select the trained face despite changes in position.

The result fits the species’ natural lifestyle. Archerfish must judge targets against complicated backgrounds, compensate for refraction at the water surface, and aim accurately from below. Toxotes chatareus is an estuarine and freshwater archerfish, and its diet includes insects, crustaceans, small fish, and plant matter.