There are several things that can happen to deep sea creatures that are brought up to the surface, but none of them explain why the blobfish becomes deformed. Blobfish don't have swim bladders, so that can't explain it. I'm pretty sure water isn't compressible enough to noticeably expand from the decompression. Wikipedia wasn't able to answer my question.
$\begingroup$ "Yes they do" referred to the article and the wiki answering the question. The linked post indicated "the bends". The Wikipedia page specifically states: "The popular impression of the blobfish as bulbous and gelatinous is partially an artifact of the decompression damage done to specimens when they are brought to the surface from the extreme depths" - i.e. it's in all the tissues that dissolved gas comes out within the cells and between them (as in the bends). $\endgroup$– Jiminy Cricket.Dec 31, 2021 at 3:04
Blobfish don't have swim bladders, they also don't have a lot of other things we associate with surface animals, like much of a skeleton or many muscles. This is fine under the extreme pressure they live in, the pressure alone provides much of the bodies support, but on the surface tissues that are nice and rigid at depth become soft and droopy.
Also water may not be very compressible but that does not mean they do not subject the tissues containing them to pressure, especially when there a drastic difference in pressure, especially when you consider that that water at depth is almost 20 degrees colder than surface temperatures. Then you also have osmotic effects since the osmotic balance at 1000m down will be different than the surface, their tissue may well take on water as they are raised to the surface.
Finally and most importantly, it is not just water that is compressed, gasses like oxygen and CO2 are also present in their tissues (and in sea water), which can most definitely expand, this is why rapid decompression kills humans so often, dissolved gasses within tissues outgas. The bends are not your lungs over inflating, it is dissolved gasses in your tissue suddenly not being dissolved.
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