What is this?

[wamp]

do you know what this is?
It is flat and black on top.. white on the bottom and it has very strong sucction..
right side of pic.. at the water line..
have alot in the tank.

 

[kev]

I dont see the pic.. <img src="graemlins//eek.gif" border="0" alt="[eek]" /> <img src="graemlins//confused.gif" border="0" alt="[confused]" />

 

[cyn]

I would guess that it is either a sea slug or a young snail. If it is hard on top, then the snail. If not, a sea slug. It could be a nudibranch, but I would have to see the other side to tell. Most nudibranches are patterned and or colorful, but some are drab.
You could do a search on nudibranches and see if something looks like your critter.
HTH,
cyn

 

[wamp]

Have searched and searched and come up with nothing. It is hard on the back but never grows an external shell.. it has a flap or a cut in the back that comes open and there is white underneath. I will disect one and post the pic of the back of the thing..

 

[wamp]

Better Pic

 

[wamp]

You can see his little antenna at the top of his head which is facing down..
P.S. even though his shell is hard it can bend with his body.. i mean he can curl up but it is not like bones, more like bendable plastic..