Large Growth on the side of my Stendker Discus

[dalmatia]

Wondering if anyone has any idea what this growth is on the side of my discus. It started small several years ago and has actually burst several times with the contents being white and cheese like. Then it covers over again and continues to grow. It does not appear to bother the fish in any way, as it acts as if the growth is not there. Fish are all very well fed with a variety of frozen, dry, and homemade beefheart mixture which is what this guy prefers. Temp 82f, ammonia 0; nitrite 0; nitrates high at 40. I really have not tried to treat it, but it is getting very large. Community tank...no other fish including 4 other discus have anything like it. Heavily planted tank of 90 gal plus 30 gal sump and flu all fx6, and nitrate filter. Thoughts anyone?
126613

[Shan_Evolved]

Maybe long exposure to higher nitrates or any other bacterica that goes invisible to your test kits? Try larger more frequent water changes as well as wiping down your glass/decor and trying to pick up any decaying organic matter in the tank

[jeep]

If it bursts, oozes then heals over 2 years, my guess is a cyst of some sort. Aside from lancing and disinfecting it, I don't think anything else would work...

The next time it bursts, take a real close look and see if you can see a parasite in there :confused:

[danotaylor]

The fish behind the one in question has a discus pimple as well. I agree that long exposure to high nitrates is the likely culprit and it looks like a huge burst pimple/abcess...
Keep your nitrates <10 and add salt @ 5tbsp/10gal and replace with each water change.