I have a few broken terracotta plant pots in the garden and I'd like to put
a few of the pieces in my tank as hiding places for my fish. I'm going to
boil the pieces for a few minutes to sterilise them, but I'm worried about
my fish, particularly my algae eating catfish injuring themselves on any
sharp edges where they broke. How would I best smooth these, or should I
just put them in the tank as they are?

Marcus