I have tried a bristle nose pleco and snails with my Oscar.. Dropped the pleco in at night in the 3d background hiding cave , in the hopes that the oscar would not notice him, but he ended up as oscar food before he could even produce bioload! Snails are a great Oscar snack i found out.. Didn't try anything else..
Just want to share my experience with algae: At a certain time of the year, the sun shines right into my tank for about 2 hours a day. It is amazing the amount of algae grow where the sun hits! I try to put blinds down at strategic spots to mitigate. I also do tons of water changes (approx 50% per week) and have just one Oscar in my 90Gal. so a relatively low bio load. I also shut off the lights during the day, only having them on a couple of hours in the morning and about 5 hours at night. As a result i have hardly any algae growth at this point. Good luck!
