Should I be worry about its growth? A few is good for the tank, but hundreds?
Well, you know, I have thought about this and this is what I have come up with. They don't get very large from IME
. They also blend right into the rock so they are hard to see. They eat algae which is a plus and don't harm anything else. They also don't appear to have a long lifespan. I say a few dead small ones yesterday. The hermits were having a field day. They also lay their eggs just above the water line. They look like little brown "sacks" that are about 1mm in length of shorter. You could easily remove the eggs every time you see them to help control them.
I am not too worried with them. I may have overexaggerated when I said hundreds. Perhaps dozens was a more accurate term.