This is an exclusive clip from the Deep episode of Blue Planet II. At the bottom of the ocean there are brine pools which have a salinity level three - eight times the usual sea level. When a Cutthroat eel gets too close it goes into toxic shock and is lucky to make it out alive. Subscribe: http://bit.ly/BBCEarthSub WATCH MORE: New on Earth: https://bit.ly/2M3La96 Oceanscapes: https://bit.ly/2Hmd2kZ Wild Thailand: https://bit.ly/2kR7lmh Welcome to BBC EARTH! The world is an amazing place full of stories, beauty and natural wonder. Here you'll find 50 years worth of astounding, entertaining, thought-provoking and educational natural history content. Dramatic, rare, and exclusive, nature doesn't get more exciting than this. This is a commercial channel from BBC Studios. Service & Feedback https://www.bbcstudios.com/contact/contact-us/