Can someone ID this snail?

[Rice Reef]

Hi All,
Just found this snail crawling up the side today. It's about no more than 1 cm in length and it is the first time I've noticed it and perhaps someone can tell me if this is good or bad.
Here are the pics I took with my iPhone ( was in a rush). Have it trapped in a clear container for now... Pics from the side, top and bottom...








Thanks