foxface

Hi! I have a YOUNG onespot Foxface in my FOWLR tank that's been up and running for about a year. I'm considering adding macroalgae or making this a planted tank. However, with the way my Foxface eats, I'm worried that they'll eat everything I put in before it has a chance to grow and be abundant...

I added a rabbitfish to my 150 gallon FOWL tank a couple of days ago. I didn't notice it the first day, but the second day I saw it had a pink lump on its mouth. Can someone help me identify it as well as know how to best treat it? my water parameters are 0.0 ammonia, 0.0 nitrite and 0.0 nitrate...