What creature is this? A snail?

[normal]

Hi all,

I've set up my tank a few weeks back and it's still cycling, although ammonia and nitrites have been consistently zero through the last week.

Yesterday I found a creature that I've never seen in my tank and I'm not sure if it's ok to leave it there or not.

It moves like a snail, seems to have a hard shell, and I only saw it at night. I turned the lights on to video and fotograph it, and after that it went to hide in a hole in the rock.

Sorry about the quality of the photos, but creature is smaller than 1 cm, and I couldn't get anything better than this:

 

[reef lover]

Looks like a bivalve going for a walk about.

 

[normal]

Is it reef safe? Should I remove it?

 

[VKP01]

I second bivalve. It’s harmless.

 

[Phycodurus]

i respectfully don’t know of any bivalves (in the reef trade that arrive as hitchhikers) that would move around as quickly as i think you’re indicating. i vote stomatella snail ... maybe even the chance it’s a chiton.

can you discern a foot (a snail’s mantle foot) as it creeps along? how about feelers?

 

[reef lover]

Bivalves move pretty fast when they want to. They use their foot to mobilize.

 

[normal]

I think it's a bivalve. It has stoped moving for the last 2 days. Should be ok