I can't remember when was the last time I've had sick fish. It happened now, and for the worst of it, to my favourite fish in the tank- my male blue Ram. I have this poor guy for more than 2 years and I never had any problems with him before. But few days ago something started to grow on his head behind his eye. It looks like a tumor or something and it's larger every day. He act normal, eat like he usually do and he shows no signs of stress. All other fish in my tank are fine, I checked water parameters and everything seems to be normal- nitrate and ammonia levels at 0, ph at 6 and temp is steady at 80F. I transferred him to my 10g tank where I kept leftovers of my shrimps and started to dose tetra lifeguard all-in-one treatment that I bought just in case several months ago. I snapped a picture of him so it will be easier to diagnose his condition. If you know what it may be, please help me, I don't want to lose him. here's the picture, hope that helps.