Help me id snails

[Carissa]

I was out on the beach today and found these snails. They were all on the rocks and such, it looked like they would be submerged in high tide and in low tide they sort of close up and stay stuck to the rocks without moving. It's the North Atlantic ocean if that helps. I'm wondering what they are, what they might eat, and if they would be any good for a warm saltwater tank. This time of year the water is probably around 65 - maybe 70 degrees in the bays where I am but in the winter it freezes.

This snail was one of the larger ones, it's no bigger than 1/2" in diameter.

 

[Carissa]

I think it's the common periwinkle, Littorina littorea. Evidently it eats green and brown algae and diatoms, but I can't find out if it will live in warmer temps or not.

I did find something that said that the minimum lethal temperature for one hour exposure is 41C.

 

[BigRedSpecial]

Yep I was going to say Periwinkle too... not sure how they'll handle warmer waters, but based on Margarita snails, I'm assuming not good.

On the plus side, people do eat them

 

[Carissa]

I have two here that I brought home to id that I thought were dead....turns out they were alive. So they're in a tiny tank now, I'll see how long they live. I fed them a little tiny piece of an algae wafer. Not sure if they'll eat it or not.

 

[bigtex52]

They would do fine in a reef. The biggest drawback is that they have an irresistable urge to crawl out of your tank up above the waterline, just like where you found them. Unfortunately for them, the high tide which would signal them to come out never arrives and they will stay stuck there until they just dry up and die.