Black velvety snail foot-like mass in Xmas tree rock, ID?

[dendro982]

Can you identify the black velvety retractable mass, living in the Christmas tree rock:

No head was found, retracts with the speed of the snail, really black - no details are visible, except some bluish hint and folding edge.

Good, bad, any special requirements?

 

[Flamehawk]

Most likely a Scutus unguis. I used to have one, they're pretty cool except I found out recently that they can have a taste for soft corals. I never found mine in a guilty location and in a large reef tank I'm willing to make sacrificies. hehe

 

[Flamehawk]

On second thought if it retracts it might be a black peanut worm. Does it look like a worm? They are harmless detritivours if so. Take a look a hours after the lights go off.

 

[Flamehawk]

http://www.racerocks.com/racerock/eco/taxalab/bio2002/phascolosomaa.htm

 

[venwu225]

Actually its not a peanut worm or a snail, its a bivalve that borrows into the coral (which cause basically no harm) base rock and the black area you see its actually the black siphon in and out take. It makes it look like a black hole, and confuses predators. Theses are filter feeding bivalves that will eventually starve to death with out large amounts particulate food.

 

[dendro982]

Thank you - it worked: I tried to see it at night, the mantle retracted and the elongated white scallop-like shell was visible for some time, then the mantle covered all again (despite of night time).
Somehow it just didn't happen to me before - to look at all of this at the night. Do you have any other useful tips, like this? Really simple and eye-opening

Sorry for being late with reply - my computer is out of order for a long time, first time in a several years. Working from another one, without any data.

Back to the topic: feeding this bivalve mollusk. This is the tank of Christmas tree worms with porites, well fed by the particles of different sizes (250 to 10 micron and even less, and zoo, not a phyto origin). 3x daily, to the light cloudiness of the water, and left so without filtration for 2.5 hrs. Then filtration is on. It's a well-lit place, as required for porites.

Anything else, what can be done?
I already had read atricles of Toonen about feeding fire clams and Christmas tree worms, and trying to use this in my practice.