Nototheniidae, commonly known as icefish, are a family of fish found primarily 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 where other fish might struggle. These fish play a crucial role in the Antarctic ecosystem, serving as prey for various marine animals, including seals and penguins. Nototheniidae are also important for scientific research, as their adaptations to extreme conditions provide insights into evolutionary biology and climate change impacts on marine life.