Limpet ID, Reef Safe?

[Kakabub]

These guys are starting to pop up all over my tank, about 3-5mm in size, a lot of them are congregating around the rim of the tank. White, yellow and brown in color, some of them have holes in their tops and some don't. I know they are limpets and it seems that opinions are mixed as to whether they are reef safe or not. Haven't seen any of them even near my corals and would love to keep them if I can. Do they become a nuisance and overpopulate tanks?

 

[SushiGirl]

All you can do is keep an eye on them. Usually they're sitting on what they're eating, so on the glass I'd guess algae eaters. Doesn't mean they won't switch to something else when there's no algae though.