A sick (?) Angelfish

Hello all--
I was wondering if anyone has ever had an experience like this one, and what you did to help the fish. Here's the story:
I bought three medium-sized angelfish from a lady on craigslist about a week ago. I planned on QT'ing, but the QT tank's cycle had gotten screwed up, and it was ammonia city. (Should have tested it beforehand... grrr) So anyway, I just put the three angels in my 110, and the male of my current pair got his pants all in a wad and started being mean. So I pulled him out and threw him in with the fancy goldfish (haha, talk about a shock -- he straightened up his act pretty quickly). Anyway, so there were the four in the 110 -- the 3 new ones, and the female I already had. The female I had got friendly with a silver-striped angel, so I'm guessing he's male.
Water quality: ph: 6.4, ammonia: 0, nitrite: 0, nitrate: 20. Temp is around 78. Water changes: 30 gallons weekly. Filtration: Fluval FX5.
The problem is that the silver male hasn't eaten since he got here. I feed a mix of thawed spirulina brine shrimp, bloodworms, and glassworms daily. No one else can resist, including the other two angels that came in with him. Also, he has begun to swell in the tummy area. He's acting lethargic. No other physical problems, from what I can see -- he looks fine, his eyes look clear.
I know some fish just don't make it through transport, the shock of a new home, etc., but what else could be the issue? Any help would be great. Thanks.

 

Why isn't it good for the angel to be with goldfish?
I think I will try the Epsom salt in our 20 gallon qt. The water quality is back to normal there. I think at this point that I'm at the last resort, because in my experience, when angels start going south, they don't usually recover fully. I'd like to nip this issue in the bud before it gets too late.
This is a fish that ate Tetra Min tropical flakes until he came to live with me, so I don't think he's very picky. I did try to throw in some flakes, just to see if he would eat them, and he won't. I also tried some different Hikari foods.

 

I will try live blood worms, I think that's the only think my crappy LFS carries. I didn't think about the "shock" with the salt. I've never used it, so I'm not familiar with the effects. I'll go with live foods, and I'll try to see if he'll eat some pieces of the peas I give to the goldfish. In the meantime, I'll research Epsom salt use, so I'll know what to look out for.
As for temps, unfortunately, in my non-central heat and air-house, if it's hot, it's hot! All fish currently live at the same temps. I know it's not ideal, but they've all been fine for a couple of years this way. The way I figure it, if I'm hot, they can be hot. So the temps are the same in all tanks. He really doesn't mix up with the goldfish much, pretty much stays to himself. The reason I took him out immediately after I saw the aggression is that he previously really beat up on the female I had. I separated them for a while and have had no problems since re-introduction. They started breeding again immediately, which I thought was funny.
Thank you, you two, for your help. I'll let you know how it goes.

 

As an addendum to my last post -- tanks that should have heaters do. I'm not freezing my fish in the winter!! Sorry, had to add that.

 

GH and KH I don't know exactly, because it's been a while since we tested. Our water is soft. The others are included in my original post. I will test GH and KH tonight. Also, I have tested all tanks for copper because someone gave me a free test kit... none have it. LOL always good to know.

 

Pet World on Mercury Boulevard is our LFS. We try not to go there anymore, unless we absolutely have to. As for the temp on the 110, I don't want to go too high because of tankmates, most of whom prefer around 78 or 80. And the pH is usually pretty steady in all of our tanks except for the saltwater, where we add 8.4 to keep it up. But I think that's pretty normal, as 8.4 is kind of high to keep without additives.

 

I LOVE Animal Jungle. They are one of the reasons we're able to stay away from the LFS. We also went to Richmond a few weeks ago, and using recommendations from this board, visited a few stores. There are some really nice stores up there. If we're not in dire need of something, we also order online. There are ways to stay away from fish stores that you don't agree with, it just takes a little more work!

 

Unfortunately, the angel died this morning. It is terrible with these fish. I have fancy goldfish that float upside down for a week, and then, after QT'ing and feeding peas, come back to normal. With angels, once they go, they go, in my opinion. So sad. The other three are doing just fine in the 110, and the meanie is still keeping his distance in the goldfish tank. Thanks for the advice... maybe next time I can act more quickly.