Personally, I believe it is a limpet (note the volcano-like shell), also a harmless algae grazer.
I saw another post after I posted mine that was very similar and they also said limpet. So I suppose then I’m going with it being a limpet. I will keep an eye on it though. Even though it’s supposedly harmless, will it stay attached to my snail forever?
Limpets, like most other snails, are capable of movement, though the larger snail’s shell would have to be flushed with your rockwork for an extended period of time for your limpet to move off. Pulling it off is not exactly an option since they are well known for their incredible ability to stick to solid objects (I remember a seashore book that recommended removal using a knife
).
You learn something new every day…Hipponix sp. (hoof snail) These snails are unique in the fact that they are sessile. Once attached to a surface they never move. They just feed on what is in reach with their proboscis. They're completely harmless. They're basically the snail version of a barnacle. Not an overly common hitchiker but when they are found, it's usually attached to the shell of a larger snail like yours.
