Unknown Critter

[Hangfire]

After reading the article that you posted Ed it does appear that I do have vermetid snails. And after giving the tank a good look over I appear to have about six of so. One appears to be more purple, but all the rest have the orange colour seen in my pictures. It doesn't appear, from the article, that they become a problem, so I'm glad about that. Thanks for the link by the way Ed.