I'm not an expert, so I just report on a personal experience. In my pond there are grass carp (20-25 lb), common carp (0-13 lb), LMB (0-4 lb), crucians (0-3 lb) and other smaller fish.
Some summer ago, due to a sudden change in atmospheric pressure during a very hot period, there was a sudden drop in DO which led to a serious fish kill.
About 200 fish died and I had to remove them to avoid hygiene and odor problems. Out of about 200 dead fish there were:
- 1 22 lb grass carp,
- almost all the larger LMB (about forty),
- about eighty LMB between 0.5 and 1 lb,
- about eighty large crucians.
No common carp died, neither large nor small.
Another thing related to common carp: when friends ask me for their ponds, being quite big fish and having to transport many of them every time, I transport them "dry", that is I put them all together in a large tub without water, then I put wet jute clothes and ice on it. I made hour-long trips like this and the carp always came safely.
All above to say that is not always true that the biggest fish is the less resistant to low DO.
