I doubt you have a keyhole limpet (Diodora aspera) since this is a coldwater, intertidal animal found here localy in California. What you have is any one of several tropical limpets commonly found in reef tanks.
Regards
Jim
"Keyhole limpet" is a generic term for any of the conical-shelled limpets with small holes at the top of the "cone." There are many tropical varieties that fit that decription. I have a small variety that reproduces in my aquariums.
Here is my question though. Yes the limpet is eating Diatoms, but would that help the cycle in any other way than just making them disappear for a while.
_________________ Mortgage life insurance Forum