This project aims to unlock the full scientific potential of a group of small, colorful fish commonly found in home aquariums—guppies, mollies, and swordtails. These fish have already allowed scientists to uncover important insights on human diseases such as melanoma and metabolic disorders, as well as in studies of animal behavior and development. However, scientists currently lack the tools to precisely modify their DNA, which limits how much we can learn from them. This project will develop new methods to enable DNA editing in these fish, opening the door to discoveries that could benefit both medicine and biology. In addition to advancing science, the project will provide hands-on research opportunities for undergraduate students and engage the public through outreach activities. It will also train other scientists in these new techniques, helping to build a community of researchers equipped to study health and disease using these powerful animal models. Poeciliid fishes are a key model system in integrative organismal biology, yet their utility has been constrained by the lack of DNA editing tools, largely due to their viviparous reproduction. This proposal addresses that gap by developing a suite of biotechnological tools to enable functional genomics in Poeciliids. The project will begin by establishing immortalized cell lines from multiple species and optimizing transfection protocols to enable CRISPR-based DNA editing in vitro. Building on recent success in cultu