Hoping these aren’t whelks. I was given some small snails as “nassarius”. They seem to have multiplied. Come out of the sand at night when I feed the tank. I don’t see them bothering any corals. They just eat the leftovers I toss in, or the algae film on the glass.
They are Nassarius snails. They eat food and detritus that sinks to the bottom of your tank plus they aerate your substrate. The are also non venomous unlike it’s cousin the Cone Snail.