I have a 9 month old Convict that has developed a white "nodule" on his side just in back of gill. I have never made any fish purchases since him and 3 brothers. No new filters, media change etc. 37 gal
tall, AQ70 HOB
, carbon used, and changed 1/month. Biomax, and sponge stay put.
My pH is 7, Ammonia 0, nitrite 0, and nitrate 5-10ppm. Temp 78 deg. Hardness GH
42ppm. I change 2/5 to 1/2 of water weekly.
This thing might be a scale coming loose, hard to tell cause he won't sit still LOL. Aggression isn't too bad but for some chasing from alpha male, but this is not the fish usually chased.