Notothenidae is a family of fish commonly known as icefish, primarily found in the cold waters of the Southern Ocean surrounding Antarctica. They are unique for their lack of hemoglobin, which gives their blood a clear appearance. This adaptation allows them to thrive in oxygen-rich, frigid environments. These fish have a diverse range of sizes and shapes, with some species growing up to 2 meters long. Notothenidae play a crucial role in the Antarctic ecosystem, serving as prey for larger animals like seals and penguins. Their ability to survive in extreme conditions makes them a subject of scientific interest.