Chennai is home to a remarkable variety of fish, including several native species that inhabit its ponds, lakes, canals and other water bodies. In this video, Dennis S. Jesudasan talks to native fish enthusiast Beta Mahatvaraj, who has been documenting native freshwater fish species across South India. He introduces us to some fascinating species found in and around Chennai, including mudskippers—fish that can survive out of water—and fish that can even “walk”. But these unique species face growing threats as Chennai’s water bodies become increasingly polluted. Mahatvaraj explains the impact of pollution on native fish and why protecting these habitats is crucial for preserving Chennai’s aquatic biodiversity.