What are these flat rigid hitchhikers ??

[youramigojake]

I recently bought a giant Neon Nepthea coral from my LFS and I found these while dipping it. Are these limpets? I couldn’t find any matching photos anywhere. They were very stubborn when trying to get them off the plug lol. Any ideas ?

 

[Sean Clark]

Chiton, good guys.

 

[EricR]

Chiton -- good

 

[youramigojake]

Chiton, good guys.

Thank you! Just put them in