im currently puting together some research on improving the oxygen carrying abilities of blood. The current large limitation on human haemoglobin is that it requires to be in a red blood cell, only about 35% by volume of a red blood cell is haemoglobin, meaning if you made up the same hemocrit equivalent of cell free oxygen carrier's you'd increase blood oxygen carrying capacity 3x for the same volumetric serum displacement of blood without increasing viscosity, i currently plan on enhancing myself with Chromium ii substituted earth worm erythrocruorin, by my estimations my blood will be bright aqua while deoxygenated and a deep indigo while oxygenated