I dont have experience with acaras and the SAE together but I've read that the SAE will become more aggressive at is matures and can latch on to the sides of some flat sided fish. Never seen it, just read it. I had a SAE and it was a great cleaner but would chase my oscar around until the oscar ate it. Guess the oscar got tired of being picked on.
A bushy nose pleco would be good in your tank, and it stays small.
A bushy nose pleco would be good in your tank, and it stays small.