Angelfish has stuff on its fins

[law67]

I have Lamarck's Angelfish (Genicanthus lamarck) in QT for about two weeks. QT is 20 gallon with HOB filter and s.g. is 1.010.

I notice the fish has white stuff on its top and anal fins. I am wondering if anyone can identify whether this is a disease and the treatment.

I have 4 picture attachments.

Thank you.

 

[Dmorty217]

Looks like lymph. Caused by stress, good water quality and enriched varied diet should reverse. Could take several weeks to months in some cases

 

[Nina51]

agreed. my kole tang had this while in qt. foods soaked in selcon and/or vitachem cleared it up in about 3 weeks.

 

[ThRoewer]

Yep, Lymphocystis. You see it often with fish that come out of copper treatment. It's often a sign of a compromised immune system (stress, bad water quality, ...), but not necessarily.
It is a virus infection that causes cells to grow many times their normal size. Normally not dangerous. Good water quality and adding immune boosters like beta glucan to the fish's food will usually help.
It seems there is a particular virus for each fish family or even species, so it is usually not infective to other fish. But once the virus is in your system every new fish of that species may get it until his immune system developed the ability to fight it.

More info about it here: http://edis.ifas.ufl.edu/fa181