I have been noticing what I though were flatworms in my return lines over the last couple weeks. Today it looked as if they had finally made it into the tank. I had about 10 or so attached to my returns. I decided to take them out manually but to my surprise they don't seem to be flatworms. They have a shell that comes to a bit of a point & have a tight grip. I'm assuming that they are some sort of snail, just have no clue what type...good, bad. etc. Anyone ever ran across these and provide a positive ID? One flipped over & key to show how small they are.