Fish problems

[Squiddy]

I went out and bought a Flame Angel on Saturday thinking that it would be a nice, compatible addition to the tank, but instead have been having problems ever since.

I added the Angel on Saturday morning and aside from the initial, expected harassment, he seemed to be swimming around and doing alright. I woke up Sunday morning, and found him hiding in the back corner of the tank with a few Ich spots on his face. I noticed that every time he would try to come out into the open, my Hippo Tang would go after him. I was told to watch the Ich, and if it got any worse, try and get the Angel out of the display tank and treat him. I came home from work today, and found my Coral Beauty lying dead in behind the rocks with most of my hermit crabs crawling around on top of it. I have no idea why he died.. the tank parameters are just fine and I doubt the Flame would have come out of his corner.

I managed to net the Flame Angel out of my main tank and have now have it in a 5 gallon tank filled with display water and with a rock, heater and a powerhead.

Do I need an air rock in the hospital tank? I have the powerhead pointing up at the surface to keep the surface moving but I have heard that adding an air rock can raise the PH significantly.

The Angel is breathing quite hard and won't eat. I added a drop of garlic extreme to the water because that's what the label said to do if the fish isn't eating. I don't know what to do now. I know I need to treat the Angel for the Ich but I still fear the if I put him back in the main tank, he will just end up in the corner again. I can't stand seeing fish like this.