Silver Dollar with Popeye and gill plate damage

[BornABruin]

I have Silver Dollar fish (approximately 8 to10 years old) with popeye in one eye and what looks like a growth and/or damage to the gill plate -- both on the right side. The fish might also have a small growth on the left gill plate. I first noticed the condition on Friday. The fish normally doesn't show the side its right side so the condition might have been there a few days longer. I'm currently assuming there is an bacterial infection, so I started doing a coure of API Fin and Body Cure (Doxycycline Hyclate - day 2 of 4) and Friz/Mardel Maracyn Two (Minocycline - day 2 of 4). I'm not seeing an injury to the eye. I've never dealt with popeye before, so any suggesations would be appreciated -- his the right course of treatment? Could I have misdiagnosed this and have a fungus problem?

Thanks in advance,
Eric



Tank size: 10 gallons
tank age:: 7 years
pH: 6.2
ammonia: unknown
nitrite: 0
nitrate: 10
kH:
gH:
tank temp: 75 deg F


Fish Symptoms (include full description including lesion, color, location, fish behavior):
Popeye in the right eye and growth of some kind and some disfiguring to the rightr gill plate. The fish also might have a small growth on the trailing edge of the left gill plate. It is breathing harder than usual and at rest is slightly head down angle (as opposed to being straight and level).

Volume and Frequency of water changes:
Two 30% water changes in last three days (one before I started the API in and Body Cure and once after day 2).
Normal changes are done about every 3 to 4 weeks (25-30%)

Chemical Additives or Media in your tank:
Aquarium salt (with water changes)
API Stress Coat + (with water changes)

Tank inhabitants:
One

Recent additions to your tank (living or decoration):
None

Exposure to chemicals:
None

Digital photo (include if possible):

 

[Utar]

I have not had to deal with popeye as of yet, so the only thing I can do is refer you to this website Popeye Disease In Fish: Causes, Treatment & Prevention.
I don't know silver dollar fish, so I just read up on them. Ten years is about the life expectancy on the good side for these fish. So getting old, really old for the poor guy can lead to a weakening immune system, making him more likely to succumb to infection.