Beta Fish, are they kind of dirty fish........?

slimy like I mean, I made sure I put her in a very clean bowl and very clean river rocks & very clean sunken ship, but after setting it up, there were these permanent bubbles that formed around the top edges of the water and clung to the gl, I dipped them out the first time, but the next morning they were back again, is this normal for Beta's? How can such a little fish be so slimy like, oh yeah the bubbles are slimy/sticky.....She's so pretty in this 3 gallon beautiful bowl I have on the table, she goes in and out of her ship, so she likes her new home, there's no way I'll get rid of her, but I was just wondering if this is normal or if I'm doing something wrong, I only feed her twice a day about 3-4 pellets, if she doesn't eat them after about 10 minutes, I take the old pellet out, these are pretty close to the instructions I was told. I've never seen one these favorite colors combined that I love, Peaches/Orange-Purples, so she's staying even if I have to deal with the slime. Any help would be Great!