Angel fish and disease

[my2rotties]

Are angel fish harder to keep then most other fish like tangs? I sadly lost my Emperor angel last week due to hemorrhaging and bruising much like my Majestic the week before. All other fish are fine. I put both fish in the freezer and now they have blood coming out of the bruises and mouths. Both were form the same store, and my other angels are fine. I had them since I started the tank back in December and they were fine and suddenly got sick and died on me.

I did not want to post about it since I always get the answers about my system being too new and I added fish too quickly. I bought these two angels a week apart and they died a week apart. Same symptoms and died the same way. I noticed the colour faded on the two of them, but they were eating and active, until one morning they were not. They could not breath and were surfacing to the top of the tank to get air. The Emp was worse and displayed fading colour and would be at the top of the tank a lot a few weeks before dying. I thought it was just quirky behavior since he would go swimming off and nip my corals afterward. He was eating and seemed healthy otherwise. He was sick for awhile now that he passed away but I did not really know until he was half dead the other morning. The Majestic was much quicker in symtoms and death. However she was really small.

What kind of diseases would cause this and why is it only these two fish? I am watching everyone else very closely but they are all active and colourful. I found my angels are not as interactive as my tangs but thought it is just the nature of the species.