Cycling with fish is always a bad bad idea. You need to stop buying fish even if the LFS
says you can, most are out to make money. What better way than to keep selling fish to someone just starting out. Get your test a liquid kit and start testing for things like ammonia and nitrites. Your ammonia should be 0 before putting in any fish. Saltwater is a hobby where only bad things happen fast.
You need to start with less delicate fish. An angel isn't a very hardy fish and especially the flame angel, when I was researching them I found there was a high unknown death rate the first 3 months. Some cardinals like the pajama cardinals are considered hardy bangaii unless they are tank bred have a high mortality rate as well.