It does - but there are a lot of factors that go into it and presumably trade-offs to the increased thermotolerance.

So one drastic example - when corals bleach they can recover with a different type of algal symbiont than they had before.

In the Caribbean, we've seen a proliferation of a particular thermotolerant type since the 1990s, and we know this algae doesn't share as much sugar (energy) with its coral host.

So in the Florida Keys, which has species that are mostly dominated by this symbiont at this point, we saw a disease outbreak that started in Miami and spread all the way to West Palm and almost to Key West.

We don't yet know why the outbreak was so damaging, but a good guess is that the corals didn't have the energy reserves (i.e. they were "run down") to combat the disease because they housed these more thermotolerant, but less productive symbionts.