I think temperature (within the range of this poll) has a greater impact on fish than corals. Corals will adapt to a variety of temperatures and seasonal temperature swings quite readily, and while their metabolism might increase/decrease depending on temp, it's already quite low in comparison to fish. I think running a high temp is more stressful to fish, both because of higher metabolism and lower dissolved oxygen at higher temps.
I have 8 fish in my 93g cube, and run my temp just below 78.
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