Oto size baby bristlenose would be fine. I plopped 2 in my discus tank a few months ago and it was a long time before I saw those buggers but I knew they were still in there since there was no film and diatoms. They were working when I wasn't looking and resting amongst the driftwood cracks. I just took a nice female out of that tank this morning. She's grown just as nicely as her siblings in the growout tank and has not had any zuchini like they have. She's a darker yellow right now too.
