Biomarkers, including acetylcholine (ACh) and acetylcholinesterase (AChE), gamma-aminobutyric acid (GABA), dopamine, neuroendocrine markers (serotonin and melatonin), and oxidative stress parameters, such as reactive oxygen species (ROS) and superoxide dismutase (SOD), were analyzed to elucidate the underlying mechanism of lead-induced behavioral disorders in adult zebrafish at a cellular and molecular level. This evidence concerns the gene ACHE and Atypical behavior.