Calyptraea chinensis??

[littlehermit0]

No way, these hats were alive the whole time on my hermit crab, but all I need to know is, are those actually the hat snail things that are glued to rocks at the beach?

they never moved, they were always on the crab, my tank is basically a warm coast design, so I really need things that I see at the beach like barnacles, crabs, algae, coralline and most importantly those hat snails

 

[ISpeakForTheSeas]

No way, these hats were alive the whole time on my hermit crab, but all I need to know is, are those actually the hat snail things that are glued to rocks at the beach?

they never moved, they were always on the crab, my tank is basically a warm coast design, so I really need things that I see at the beach like barnacles, crabs, algae, coralline and most importantly those hat snails

With the tube/mouth (called a proboscis) visible in the pic, that tells me this is probably a Hoof Snail (taxonomic family Hipponicidae) rather than a Slipper Limpet/Hat Snail/Cup-and-Saucer Snail (Calyptraeidae):

Yeah, looks like either a Slipper Limpet (genus Crepidula) or a Hoof Snail (taxonomic family Hipponicidae) - both are harmless; slipper snails are filter feeders, and hoof snails feed by extending a long proboscis (think like an elephant's trunk) to eat either their host snail's waste or any food it can reach from its host's back.

As a note, at least some Calyptraeids are mobile as juveniles, and will feed like regular snails by grazing - as late juveniles/adults, though, they're sessile filter-feeders.