from my experience i would ruff up the outside of the pvc. On my first ones i added to the pond i don't see many fish around them. I don't think they feel much comfort in being against something white where they stand out. After ruffing the pipe up you will see more of mother natures plants and animals attach thenselves to the pipe which make the pipe more natural and may hide the fish alittle more.
Maybe hit with some green spray paint? Would be much easier than scuffing that much pvc
