but to play that game, you also learn about adaptation in high school
The fundamental confusion here is the notion that, absent one's own personal expert credentials, we have no access to any expertise or authority of any kind that can be brought to bear on this question (funny that that requirement applies only one way).
The vital role of coral in supporting marine ecosystems is a general and well understood phenomenon. So much so that our ordinary access to expertise through science communication in the media, our summary of this understanding as reflected in high school education, and, if needed, in major reports from NGOs is sufficient to address the question and indeed is central to the purpose of those respective institutions. Those are access to pertinent expertise for this kind of question.
I promise you, that this consensus has not overlooked the possibility of everything being made right by adaptations later on as you seem to be implying, and I promise that no version of explanations of evolutionary adaptation has ever taught that adaptation guarantees, as a cosmic law, compensation for the destruction of ecosystems. The same resources noted above are sufficient to dismiss this as an ordinary biology 101 confusion.
I think you need to be more careful about what your unqualified promises are.
As for the effect of coral bleaching on fish, you can google it and I've definitely read about it before, seen ecologists talk about it, etc. The expectation is that it will reduce the number of fish significantly.
https://scripps.ucsd.edu/news/central-pacific-coral-reef-sho...