Marine researchers have landed the deepest fish ever caught off Australia from 6.5 kilometres under water.

The two new unnamed species of snailfish have faces frozen in a frown like a sad clown and bodies made of translucent gel instead of skin and scales.

Deep Sea Research Centre founding director and UWA professor Alan Jamieson told 6PR Breakfast they used a yabby trap bought from a Perth tackle shop, which they tied to a $100,000 piece of scientific monitoring equipment resistant to extreme pressure, to snare the rare fish.

The research centre was established recently to map what species exist in the deep waters off WA and Australia, with about 13 uncovered already.

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