The deepest-living fish on Earth is a pale, boneless-looking tadpole of a creature
The Mariana snailfish lives up to 8,000 metres down in the Mariana Trench, deeper than any other known fish, where pressure is over 800 times that at sea level. It copes by staying small, soft and nearly translucent, with an incompletely closed skull and bones so poorly mineralized they barely show up on an X-ray. No other fish has been confirmed living deeper.