I've had this betta for just a couple weeks and there are some things that concern me. First, is his head. He has these red spots on his head and I can't tell if it's discoloration on his scales of if he's missing scales. I can't remember if he looked like this when I got him, but I just noticed it about a week ago. I'll attach photos. Could this be some kind of disease that I should be worried about? Second, he seems to just stay on one side of the tank, at the bottom, right beside the glass. Sometimes he just stays in one place but most of the time he paces back and forth along the glass. I can't tell if he's just guarding because he sees his reflection or if he's rubbing up against the glass because of some parasite or illness. He's my first fish so I don't know much. He's in a 20 gallon with live plants and five snails. He eats fine. I did have a pretty bad nitrate spike the other day because I accidentally left some uneatten food in the tank, so I don't know if that could have anything to do with it. Thanks in advance!!