cleaner shrimp

What's a good tankmate for an asian and a silver arowana (seperate tanks). I don't mid snails, crustaceans, fish or anything just that it can eat various type of algae, doesn't bother the arowana and wont be bothered by the arowana and dosen't have a huge bioload.

Does anyone else enjoy having their hands cleaned by their cleaner shrimp? When they see me approach the tank they move to hang around the filter area where my hand usually goes in. Waiting to clean my hands. Do you think they would get much nutrition from this? I was wondering if rubbing sand...