Freshwater limpets?

Okay so if limpets were worth anything I'd be rich right now... How do I get rid of them? xD they have gone crazy! In preparation for changing my substrate I've barely fed the fish, I do multiple water changes and gravel vacs each week and still their population has exploded! There's algae for them to eat but if I got rid of it I'm sure my otos would starve any easy solutions?
I'll put up a pic in a bit.