*2.2.2 Zebra fish (*Danio rerio*)*

Owing to its large number of favorable properties, Zebra fish has been used widely as experimental animal for various diseases. Zebra fish are inexpensive, easy to conserve, develop rapidly, and breed in large quantities. Larval zebra fish are also extensively used in toxicity screens since they have a permeable skin through which substances added in the rearing medium are effortlessly taken up. This permits for

greater control over dosage and ease of administering substances to large numbers of animals. Furthermore, larval behaviors can be exploited in assays to test the effects of the treatment. Being a vertebrate, the central nervous system of larval zebra fish expressions an extremely homologous to humans. Therefore, toxicology studies performed on larval zebra fish can be very helpful in deciding the putative targets in humans [50]. Thus *Danio rerio* commonly known as zebrafish is a charming popular animal model for treatments in neuropharmacology and pharmacogenetics. Both the adult and larval zebrafish are presently studied to increase the understanding of central nervous system's function and dysfunction [51]. There are various studied reports by Gerlai et al. on the latent learning, behavior, and memory alteration of adult zebrafish [51–55]*.* Apart from fish, there are several other experimental models.
