I put an apple snail in my 10 gallon last Sunday, and I can't believe what a great job he's done. The glass and rocks are spotless, even the rocks with bits of starter plants tied to them. He cleaned all around and over them without touching the healthy green stuff. Now he's started on the plants, going up and down each one, and they seem to appreciate having clean leaf surfaces, everything looks healthier. I named him Zamboni. What a nice addition (so far) to my tank! It looks so much better!