Ok in the last two days I've pulled two small starfish off the glass in my tank. And today I saw a small (I mean like size of a pinpoint) creature that I saw swimming around the sand. Hard to say what it looked like because it was so small but I was wondering if these r things I need to worry about. I looked around and didn't see any of either of these things. I use a dip for the last few purchases but there were a few in the beginning that I didn't. Any ideas of what they could be or ways to control them if they're problematic.