Bubble Algae Looking Thing Stuck to Juvenile Angel?

[h2so4hurts]

I have a juvenile Chrysurus Angelfish I added to my tank about 3 weeks ago. Upon receipt he was formalin/malachite green dipped for an hour. He was QT'd for 3 weeks. 3 weeks of 60mg/gallon Chloroquine with 50% water changes every other day. Final week of QT I added metro/praziquantel treatment to the Chloroquine treatment. No apparent disease, ate very well in QT. About a week ago I noticed a black blob on his side. The blob has now grown to about the size of a pea. It looks like a black pea stuck to the side of the fish. I have never seen anything like this before. Any ideas? There's no way I'm catching him to get him out for observation or treatment so this is more of a question of whether others have seen something like this before. It literally looks like bubble algae is growing on the side of the fish. He doesn't seem bothered by it either. Not flashing or scratching. No other fish have this, he's in a 500g mixed reef. I can't get good pictures of it, it's a small fish in a big tank and a black blob on the black part of the body...

 

[Big G]

Could be a cyst or a tumor. Cysts can be round, bulbous and smooth. Tumours usually are similar but have a more lumpy texture.
Given the fast growth, sounds more like a cyst. Not much you can do. Sometimes they are absorbed by the body. They do contain thousands of spores.

 

[h2so4hurts]

Could be a cyst or a tumor. Cysts can be round, bulbous and smooth. Tumours usually are similar but have a more lumpy texture.
Given the fast growth, sounds more like a cyst. Not much you can do. Sometimes they are absorbed by the body. They do contain thousands of spores.

Thanks for the reply. I'll keep an eye on it. I just hope it drops or pops before it starts negatively affecting him.

 

[h2so4hurts]

Quick update, It got to the size of a large pea and then fell off. There's a little white mark on his body, but I'm assuming that will fix itself. Weirdest thing ever. I did add two cleaner shrimp about a week ago, so maybe they came in for the assist.