No idea but I can bring you enough guppy grass (at the next meeting) that it's growth should keep pace with any proclivity to eat, shred or otherwise vent their passions upon.
Them aren't plants. Might you should just stick with just the hardscape if Oscars have so much antipathy toward foilage. The guppy grass thing might make for a good experiment nonetheless...
...if my Java moss grew as fast as guppy grass - even water sprite and hornwort doesn't have to be harvested every two weeks just to leave space for the fish.
Get a piece of drift wood and get some java fern or java moss. They will probably bite it and re-position it a little. Cichlids like to arrange the furniture as they like it. Interesting to watch actually.