Scientists discovered a new fungus living in the guts of deep-sea amphipods and studied how it survives in extreme pressure and low-salt environments. By comparing this gut fungus with a similar fungus from deep-sea sediments, they found that the gut fungus is better adapted to low-salt conditions and produces different protective chemicals. The study reveals that fungi evolve different survival strategies depending on where they live, using changes in cell walls and energy production to handle environmental stress.