Well I have had these discus for about a year and a half. Half of this time has been a struggle. Years ago I have bread discus. Really no issues in those days.

My parameters are ph 6.5 temp around 88, sponge filtration, 50% water changes every other day. I have 9 discus. A breeding pair of colbolt blues, another breeding pair one a snakeskin, the other a German blue. The other five are 3 red turquoise two juveniles and one adult. One juvenile blue diamond, one adult golden dragon. About a year ago they were all in a 125 gallon tank. Started noticing all the blues except for the large Male colbot turning g dark.. I noticed white worms on my glass. My female colbolt seemed to be withering away, and started seeing fin rot, specifically on her.
So I treated the tank for worms with wormer plus aquatic wormer,fluke and parasite killer. Followed the directions accordingly by a follow up treatment for heavier infestations. Noticed the worms seemed to disappear. Treated the tank with fin and tail rot. The blues seemed to pop back looking great. So I set up my two 30 gallon breeding tanks. I immediately started seeing signs of breeding with both pairs! About a week later..the worms are back on the glass on ALL tanks blues are dark again my blue diamond seems to have fin rot and I see a hole in the fin of the female colbolt. I have never in my time seen this or had this many issues. Please advise!!!