When I first noticed this spot on my damsel, it was white. I did some research and thought it might by lymphocystia, so I moved it to a quarantine tank, but now it looks yellow and less like a lump.
Aquarium is very new (about 4 weeks old) and tank mates are a blue spotted puffer, another springer damsel, a flame fin tang, a flame fin blennie, and a royal gramma.
I don't have the ability to get hard numbers on all my water conditions, I just have color-coded test strips. The salinity is right around 1.027
Is this a disease, injury, or something else? And should I quarantine?