The blobfish (Psychrolutes marcidus) is a foot-long pink fish found in the deep waters off the coasts of Australia and New Zealand. It has soft bones and few muscles and lacks a swim bladder, the gas-filled internal organ that allows most bony fish to control their ability to stay afloat in water. However, that doesn't mean that the blobfish just sinks to the ocean bottom. Instead, its body is jelly-like, with a density slightly lower than the water in which it lives. Thanks to that, it floats slightly above the floor of the ocean, where it waits for small crustaceans and other edible matter to pass by so it can suck them up for food.
Because blobfish are found only in a few areas of the world and at depths between 2,000 and 4,000 feet below the surface of the water, they are rarely encountered live. Most specimens encountered by humans are dead ones discarded by deep-sea fishing trawlers that use nets to sweep up marine animals from the bottom of the ocean in an effort to catch edible fish. Blobfish, however, die at the air pressure levels at sea level, and, therefore, remain elusively underphotographed.
The best-known blobfish specimen was found by a research vessel, NORFANZ, in 2003 and is preserved at the Australian Museum. Affectionately known as Mr Blobby, this blobfish resembles an inflatable character balloon that's lost a good amount of its helium. It is this preserved individual specimen that people associate with the name "blobfish," and it is the one that was voted the ugliest animal in a mascot contest held by the comedy/conservation troupe, the Ugly Animal Preservation Society, in 2013.
The blobfish isn't so unattractive when it's not a fish out of water, scientists think. Based on the appearance of other members of the fathead sculpin family, researchers think the blobfish looks a lot like this in its natural environment:
illustration of two blobfish in situ. Image Credit: Rachel Caauwe [CC BY-SA 3.0], via Wikimedia Commons.
Maybe the blobfish isn't so blobby after all.
You can learn more about how fish have evolved to have adaptations in keeping with their environments by building your own fish. If you're interested in other blobby creatures, watch this video about what we think of as jellyfish. Want to find out about other things living off the coast of Australia? Check out David Attenborough's Great Barrier Reef, an interactive site. And if you're curious about what makes things float, rather than sink, you can check out this lesson.