Ok so i got these snails for a GHA problem...fixed. today i noticed a little head out the back of my conch... Wait there's another email attached? U look and give your opinion. I tried to pry off. Seems connected.
Its a limpet snail. They can move but IME if they find a snail shell to latch on to,, they never move will just carried around by the snail and eat the same thing the snail eats.
I have a cerith that carries one almost half its size. They eat together on the glass. Kinda cute.
It definitely looks like a barnacle to me. If it is then you will notice what appears to be several smaller "plates" in a tightly closed position on the pointed tip. If I'm not mistaken, I can see the plates as the visibly darker section.(Think camera shutter) If you watch closely you may even see this area opening and closing rapidly to allow the brush like feeding structures to function if it's still alive. It's a harmless filter feeder.