Title pretty much sums it up. Assuming a well-mixed body of water with homogeneous, but low oxygen concentration, would a fish at, say 50 ft, experience more or less oxygen stress due to the increased pressure? This seems analogous to the situation with humans at sea level vs at altitude where the concentration of oxygen in the atmosphere is (almost) the same but the physiological ill effects are due to the partial pressure of oxygen in the air vs in the lungs/blood. To be clear, I’m not asking about a dissolved oxygen concentration gradient (e.g., due to oxygen being replenished at the surface and consumed in the sediment). For the purposes of the question, oxygen concentration is equal, only the pressure is different. If it matters, assume the fish have been acclimated, not rapidly moved from low to high pressure or vice-versa.