I don't know too much about spilos, but most fish like places to hide, driftwood is always good, and also plants - if they do eat them, it shouldn't cost too much, what harm is done?
or try fake plants.
You could try driftwood or a similar alternative but, I'd try a bare setup with just gravel for the territorial issue to die. I tried it with my reds and they all seemed better. With a bare setup, the p's will usually all shoal more.