Notothenioidei is a suborder of fish commonly known as Antarctic icefish. They are primarily found in the cold waters of the Southern Ocean surrounding Antarctica. These fish are well-adapted to their frigid environment, possessing unique features such as antifreeze proteins that prevent their blood from freezing. This group includes various species, some of which are important for commercial fishing. Notothenioidei play a crucial role in the Antarctic ecosystem, serving as prey for larger predators like seals and penguins. Their ecological significance and adaptations make them a subject of interest for scientists studying climate change and marine biology.