metal halide blind fish?

I doubt that most fish would have trouble with the intensity of metal halides, as long as there is a place to hide that is dark. As for making them go blind, that is a stretch for most fish. The only ones that I can think of that could go blind are any fish that are found particularly deep and are never exposed to bright light. Most of the fish we have are exposed to light brighter than any metal halide. Yes, metal halides are okay for dogfaced pufferfish, but why are you placing halides over a pufferfish tank? They are not compatible with most corals--certainly not ones where metal halides would or should be used.

Just wait until after the fish is moved, then. It is a waste to run it beforehand.

Coralline algae actually grows just fine in quite dim lighting. Calcium and alkalinity are more important for its growth than blasting it with light. Besides, in the meantime, you risk causing a significant algal bloom with the pufferfish and its wastes being in there. Get the tank situated and nutrient levels lower before you increase light intensity.