Somefish or something has been nipping off my cabomba plant stalks,from the looks of it,it happened at night,there are a few fish that are able to break of the stems-parrotfish,bgk,clown loaches,featherfin synodontis,black skirt tetras.I can't identify which one snaps the plants off,it is not water currents since the stalk looks like it is chewed off.