Check my signature, I have lots of otos in tanks. They are effective algae eaters, but have no scrubbing power. Then I added a true SAE, and got my tank cleaned from harder algae that otos could not touch. It is important to get true SAE, they are not territorial and will not kill your fish when they grow adult size.
Do a search on Google how to differentiate them from false SAE and CAE, if not sure what it looks like.
I have one par tank but they need company to chase each other. It is a very fast swimming fish.