The Blobfish (Psychrolutes marcidus) Is a deepwater fish rarely seen by humans.
It is found along the shores of Australia and Tasmania.
Blobfish are made mostly of jelly.
This jelly flesh weighs less than water, allowing them to float, and conserving energy otherwise spent in an attempt to stay off the sea floor.
It is also an alternative to a gas-filled swim bladder, a feature of many fish in shallower water.
At 800 metres deep, the pressure is about 80 times higher than at sea level, so any gas would be too compressed to serve the purpose.
Their lack of muscles is no hindrance – they have a feeding strategy that consists of sitting and waiting for something edible to pass.