My angelfish is sick!

[Shicoa]

Hello everyone,

I currently own a 55 gallon tank with about 10 fish in it. I have 2 55 gallon filters running on it and I do a weekly (or biweekly) 50% water change. I feed them twice a day and it varies with flakes/frozen blood worms/frozen brine shrimp.

So about two weeks ago I noticed my platinum blushing angel fish was acting a little strange. Instead of hanging out with his usual crowd of angels (there are 4 others) he was hanging off to the side by himself. Nothing had changed in the tank, no additions or anything. I'm not sure if I was imagining it or not but I think it's worth mentioning.

Anyway, about a week ago I introduced a new angelfish who was his size (about quarter size). I quarantined that angel for about 2 weeks too so I know he's got nothing wrong with him. Anyway, 3 days later I notice my platinum blush stopped eating. I put him in the 10 gallon quarantine tank by himself and tried giving him some salt treatment and as a last ditch effort I tried giving him the general cure medicine. It's not working. I noticed that the angel also started doing this strange cough/gasping thing? I did my research and saw it may be because of lack of oxygen. I got really worried because I'm really not sure if I have enough oxygen in that tank and so I put him back in his original tank. He seems to have less coughing but has that same little gasp.

I took a video of it and posted it so you can see:

Sorry for writing so much but I really don't want to lose this little guy :( Any suggestions would help so much. Thank you so much for reading!

[Cory Catfish]

Water params?
The only thing I can think of is that he has a parasite. What is the "general care medicine"?

[Shicoa]

The general cure is this: http://www.petsmart.com/product/inde...uctId=10850833

So if it's a parasite that medicine hasn't helped him out yet. Last night I saw him doing that cough a lot too. He doesn't seem to be doing it as much this morning, though...

Water params: NO3- 20
NO2- 0
pH 7.5~8.0
KH 40~80
GH 60~120

The water in my part of California is very hard and has around that pH.

[Lady Hobbs]

7.5 is pretty average. 8 is getting on the high side. Quite a bit of difference between the two.

My angel now and then does then. Perhaps it's how they release gas from their belly? I don't know but to me it would be a good thing. That's a lot of angels in a 55 gallon. They pair up and get pretty aggressive at about 6-7 months.

I would not have put him in quarantine or given him medications without knowing what is wrong tho. This is causing him undo stress.