Yes that is precisely my current problem.. My tank raised clowns decided to host on the suction cup of my heater, very near the surface of the water. I need to quickly find them a safer region in the tank.Toadstools can work, but I think Frogspawns are the most common "alternative" for clowns to host in, although clowns are not the pickiest of creatures.. they will even host near a powerhead if they feel like it.