My black moor seems to have developed some sort of growth on his side a little bit behind his gills. It came on fairly fast too because there was only a little bump behind his scales on Saturday and now it's sort of like a red pimple and is poping out from behind his scales. His behavior hasn't changed and he's eating his regular diet of gel food, brine shrimp, greens and pellets.
He's in a 20 gal. that's been set up for a little over a year with my oranda that I got a month and a half ago (my oranda went though 3 weeks of quarantine before I add him). They are both about 2" long. I have a Penguin 200 filter with a biowheel, and I do a 50-60% water change every week and I normally use Aqua Plus as a water conditioner but the last few times I used Tetra Water Conditioner.
Nitrite Level: 0
Nitrate level: 0
Ph Level: 7.2
Ph Level out of the Tap: Last time I checked around 7.0
I haven't added any medications, only 0.2% salt. Could it be parasites or have anything to do with the change in water conditioner?