As several neuronal peptides regulate food intake and anxiety behaviour in zebrafish as they do in mammals21,23 and NPY induced the stress-resilience in rats35, stress- and anxiety-related gene expression levels were investigated in whole NPY-KO brains by real-time PCR of orexin (Orx), cholecystokinin (Cck), corticotropin-releasing hormone (Crh), arginine vasopressin (Avp), isotocin, (Ist, fish ortholog of oxytocin (Oxt)), pro-opiomelanocortin (Pomc), a glucocorticoid receptor (GR) and a mineralocorticoid receptor (MR). The gene discussed is AVP; the disease is Anxiety.