Today I added an L200 high fin green spot pleco to my 30 gallon tank. He has slowly become bolder and moving around the tank. I noticed that when he was on the glass the angels peck him until he swims away off the glass. The angel side is more the left but it doesn't seem to matter anywhere on the glass get's there attention and they go after him. They have ignored all other tank residents as far as I have seen to date. When he is on the bottom or driftwood they leave him alone. What's causing this?