Orange thing I thought was a sponge...

I received some new rock today and put it in my tank before going off to do some shopping. When I got home my boyfriend was looking in the tank and said what I thought to be a big sponge or something was moving. At first I didn't believe him, but then I saw it for myself. It was kind of elongating and contracting, then it moved left to right. I don't know what it is. Any ideas??

 

is it a cucumber? i cant really tell from the pic where the animal starts and stops

 

He's attached to the rock We noticed a hole in the end at one end and the rest of the body is hanging off the rock into the water with a hole on that end. The end that's attached to the rock has hairy stuff on it, and a big clam thing about 4 cm away from where he's attached.

He was expanding/contracting all night, so I put him closer to the sand to see if he wanted to hop off the rock or something and he lowered himself so the end with the hole is resting on the sand, and when he contracts water jets out of the hole at a pretty decent rate and moves the sand, but he's sill on the rock.

Here are some more pictures one showing where he's connected to the rock and stuff.

 

It looks like a sea cucmber to me too.

 

kewl hitch hiker !!!

 

Odd looks like a sea cucumber to me as well. Not a great thing to have as a hitchhiker as they can release toxins into the water if they die

J

 

Perhaps a Sea Hare (slug). Good for eating unwanted hair algae but once algae is gone it will die and polute the tank. Keep a close eye on it and if it sits in one place for a day or so without moving it is time for it to go. LFS may take it back.

 

I don't think it's a sea hare. The sized goes between about 3" and 1.5" in length depending on what it's doing. It doesn't seem to be moving from that rock.

Here are some more pictures of it and another little thing I just noticed. He's white and about .75" long.

Any idea what the white thing is?

 

orange thing- some kind of sea apple maybe?

 

Still think it's a Sea hare of sorts. Here are a couple sites; Sea Hare
http://saltaquarium.about.com/od/seaharephotos/Sea_Hare_Photos.htm