Krill are small shrimp-like creatures that live in oceans around the world - mostly in cold water.
They feed on plankton and algae, making them high in Omega-3. In recent years there has been a growing demand for krill oil as an alternative to fish oil for Omega-3 supplements.
Krill are found in large groups throughout the world's oceans.
But Antarctic Krill are the main target for the production of krill oil. They are found in large numbers in the Antarctic and the clean waters mean that they have less exposure to harmful toxins.
This makes them a tempting target for krill-fishing companies.
A recent investigation by Greenpeace found that krill-fishing companies are becoming more active in the Antarctic, due to higher demand for krill oil.
This is bad news for penguins, whales, seals and many more species that rely on the krill for food.
If the krill disappear from these waters, so will the incredible wildlife that depends on it to survive.