Zebrafish are used extensively in the study of vertebrate genetics or development and exhibit a high degree of genetic similarity to mammals. For example, approximately 85% of known human single-gene epilepsy mutations have homologs in zebrafish. From a logistical perspective, adult zebrafish reproduce rapidly (hundreds of embryos per week from one female) and develop quickly (most organs formed within 24 hours). Due to their small size, zebrafish larvae can be maintained in small fluid volumes and arrayed in multi-well plates. Drugs can be added directly to the solution enabling rapid in vivo small molecule screening.