Exactly! These guys are great at catching particulate matter that floats around the tank. My sand had tons of them and I loved it. The fact that you have so many means that they have a steady food supply, so I would encourage you to keep them and enjoy their benefits. Most of us who've been around for a while really love things like this, so enjoy them while you can. Diversity is key to a successful tank and these guys are a part of that diversity.