Spatial cognition in zebrafish: the role of strain and rearing environment.

Two strains of zebrafish, WIK and a second-generation wild strain were reared in either a structurally simple or complex environment and compared in their ability to locate a food reward in a five-chambered maze. There was a significant interaction within subjects between rearing environment and trial, indicating that the consistency of learning varied depending on rearing environment, with those reared in a structurally simple environment showing a slower rate of learning. Fish of both strains reared in a structurally complex environment were smaller than those reared in a simple environment. Our study demonstrates, for the first time in zebrafish, that performance in a learning task as an adult is sensitive to rearing conditions during development.