Pond Boss Forums AERATION Systems questions Winter survival DO vs Hydrogen Sulfide, etc

To be sure, there are other limiting factors besides the DO. Even in controlled experiments that test for the limitation of DO there can be other contributing factors that won't likely be replicated in the lake setting. For example, the production of CO2 in such an experiment as a respiration product of the fish. It is toxic and at increased levels may contribute to fish dying at more elevated DO than in water at lower CO2 levels. I think this could also be the case with other toxins as well. You've also, wisely I think, recognized the effect of cold temperature on the metabolism. The limiting relationships as they affect fish are multivariate and so its takes a considerable amount of testing to understand them. I think the proposition that aeration assists with removal of toxins in the water is a viable hypothesis. Whatever may be happening, aeration under the ice and snow is helping your trout survive the high mountain deep freeze.