Snails eating my SPS

[DeletedAccount]

I have noticed some recession on one of the acros in my tank lately. Tried to change the location and flow and light a little, to no avail. Last night I couldn't sleep and went to spotlight the tank (poor purple tang is prob blind). There were two snail type guys chowing on the bottom edge of my sps. I took them out (snails) and trashed them, but you know that if there were two there are many more of the buggers! They are small, oblong shaped buggers that have an iridescent tint to the smooth shell, maybe even flesh over the top of the shell, but not a limpit. Any ideas? How do I save the corals from the munchers? This is my only tank with MH and if I have these in 1 tank guesses are that they are in all of them. I do not keep things seperated as I should.

[::pete::]

Possibly the 9th one down ?

[DeletedAccount]

Yes. It looks like the stomatella that I bought, but they are suppose to be herbivores and there was very little doubt that these two buggers were EATING the SPS flesh. I watched for a few minutes and there was healthy flesh in front of them and after they passed it was white.....

[prof]

I have a number of those in my tank. I also have some that are white/brown and some that are black.

I have not had any problems with my tank or livestock.

Yesterday they were 'reproducing'. At least I am 99% sure that is what was happening. Some were squirting a white fluid into the water stream and some were squirting what looked like eggs into the water stream. Pretty cool to watch.

[DeletedAccount]

I am guessing that these are a snail that looks very much like the stomatella but are not them.... Anyone have suggestions on what to do about it?

[Instar]

I have many of the stomatellas in my tank and never seen one graze a coral base. The things that will graze a healthy coral from time to time are some of the Chitons. The link above has a couple pictures (5th) down of one species, although maybe not of the one that would eat coral. I have a number of Chitons too, and only had one that ate coral. Coral flesh around the encrusting base of a colony may need to be eaten to keep it from getting RTN, but, those Chitons I have seen go over the top of my Poccolopora and grind it down smooth. They aren't really after the coral, they are just grazing on what happens to be there in the way as they looking for algaes. I do have something that comes out now and then, here and there and does a lot of damage. One night it ate half a goniopora, last night it put a clean dent in a large colony of yellow polyps. So much for not getting any nasty critters by using only dry aragonite rock.. Hitchhikers! The Chitons that I have are real close to the description of the ones you gave here. I guess they are a different species though as they are not bothering anything and live in the substrate during the daytime.

[Instar]

And another thing about the Chitons; they usually graze the same patterns, same pathways at night, over and over and can make a depression in the rocks. You may have placed that coral on one of their paths. Since you trashed the culprits, that may end it for that spot.