A few Ghost Shrimp might be a good addition. They are good little cleaners and don't seem to be aggressive at all. I have a bunch in my kids 10 gallon tank with some neons and glo tetras. I've never seen them bother the fish unless you consider riding on the snail a problem. There was a dozen shrimp in my ACF tank a month ago but there have been casualties as expected. I think 5 or 6 have avoided becoming dinner.