Nothing in my tank is looking "off" at all. Except the toadstool that I picked the first snail off of. It's been closed for the past 2 days. Other than that, they've been on my rock and on my glass. I'll try to post a better pic.
I've looked through WetWeb and don't really see any snail that is an exact match. From what I've read it seems like these little guys and girls are Nerites, but I can't find any that are specifically "Red"
Well if they are what they are...and assuming the red/pink is coralline, and it does have white...it could be Heliacus arela(sp) . They are predatory eating zoanthid polyps and yellow polyps. Here's one without the red/pink, maybe you can see if it resembles like yours?
Bingo...They are very interesting and I have been keeping a close eye on them. So far they're behaving, Strolling along the glass and rock. Only the one snail was on my Toadstool and it didn't do any damage. I have one of our club members here in Connecticut that wants me to grab a couple for him to put in his tank. The person I received some grape caulerpa from said that he had many different types of snails and that none of them are harmful. But I have been searching the internet trying to find the exact snail which so far I haven't been to lucky with. I'm going to try and get my kid to take a better picture (she's the expert in that dept) and I'll repost when I do