It is hard to say for sure the fumes built up To toxic levels and killed you fish, but it could be a factor in their death. Sorry for your loss. For your corals, I would do a water change to be on the safe side and test your water to see what the levels are. Also I would get a poly filter pad and run it in your sump or tank. It will change colors and tell you if it is pulling out any impurities from your tank.