I’m dealing with a sick pea puffer. Its eyes have turned black and has stopped eating as of two days ago. No idea what the problem is. Ammonia and nitrites are 0 and nitrates are about 5ppm. It’s in a 36 gal with a fair amount of plants (Java ferns , rotala, Amazon frogbit, jungle Val, etc.) only other fish in there are two other dwarfs and a Bristol nose. I do 35 percent water changes weekly. Lethargy and black eyes are the only symptoms. The eyes didn’t change at the same time. It was a week or so apart. At first I thought it was blindness from either a fight which I can’t say has never happened but it isn’t common or maybe too much co2. I turned off the co2 and did a water change and it seemed to perk up but then it is back to this. No new tank mates in months and this tank is about a year old. The puffers have been in there since it cycled. Everyone else is fine.
Right now it’s in a specimen container so that I’m able to keep an eye on it, make sure it has access to food and to separate it from tank mates
any thoughts or ideas? I have any anti parasite, fungal, anti bacterial, Ich-x, and aquarium salt so I’m prepared to treat it, I just don’t know what to treat for.