I have a few softies that will do well in the PC lighting of my 19octo tank mostly zoos and riccorida. Will an octo bother these or will the harm him in anyway? IT would be a nice way to get some good color in the tanks so I would like to look into it more.
most people won't recommend it. octos like to move a lot of stuff around, and will probably crush your corals in the process. Any corals that sting are not a good idea....but outside of that, if you don't mind your octo destroying stuff [and if i recall, ricordea can be pretty darn pricey], you can give it a try.
I think somebody on here said that caulerpa works okay, but I don't remember clearly so don't take my word for it.
It's interesting just to look at your octopus. You can add shells for color and texture - I believe that Carol, corw314, adds colored glass marbles, too. Your live rock will have coralline algae of various colors. So your tank can be attractive and interesting without adding corals.