Warmer water means that the amount of gases- especially oxygen- dissolved in it reduces, since solubility of gases in a solution in most cases decrease with an increase in temperature.
I'm interested in knowing if tropical fish have any adaptations to account for this reduced oxygen compared to fish in colder waters. Any modification of the gills maybe?
Referencing the below articles, I have come to the conclusion that tropical fish end up migrating to shallower waters or cooler habitats due to the oxygen depletion, showing that this decrease in oxygen is serious enough to affect them. However, this may be due to excessive heating of oceans due to global warming. I'm curious about whether fish in tropical regions have any adaptations for living in ocean water that is heated purely by natural means, not anthropogenic ones.
https://www.usgs.gov/media/images/temperature-affects-dissolved-oxygen-concentrations https://www.pca.state.mn.us/sites/default/files/wq-iw3-24.pdf https://www.sciencedaily.com/releases/2015/06/150604162455.htm https://www.nationalgeographic.com/science/article/150313-oceans-marine-life-climate-change-acidification-oxygen-fish