if their tiny, without pics we peobably shouldn't s care him to death with pyramids! ;) not just yet... they could be baby cerith! (I know... huge stretch!) I have had trochus breed in my tank, and I have a few chitons too, though, they don't look like cateripillars, my chitons look like a trochus or astrea that doesn't move very much, and they have a lacy halo of flesh around the bottom, excellent algae cleaners.
"Maybe in order to understand mankind, we have to look at the word itself: "Mankind". Basically, it's made up of two separate words - "mank" and "ind". What do these words mean ? It's a mystery, and that's why so is mankind." ~ Jack Handey