Tank setup 48 hours, this guy appeared this morning

[Ritual]

Hello all,

I setup a tank on Sunday and added the live rock, everything is looking good... I have been checking morning and night looking for little critters and this morning I spotted one. The only problem is I don't know what it could be!

It obviously came in on the live rock. I have checked all the ID threads I can find and various sites but I can't seem to find this particular brand of critter.

I apologise for the picture. It isn't the best as I took it from far and only spotted it as I was leaving the house...

Here's what I know about it:

Brown
Approximately 1.5cm-2cm long
Round, about the same height as it is wide - roughly 1cm?
Has a "split" back, look a bit like a weird peach
It moves, in the time I was watching it (about 5 minutes) it went from its spot to the top of the ridge, stopping a few times as it went.

I've attached a picture that's kind of far away, I will try and get a better one when I get home. What you can see in the picture is the entirety of it that I could see as it moved about. There were no legs poking out.

It's much bigger than I was expecting a hitchhiker to be after only 48 hours. That made me panic a little bit. I was looking for tiny baby sea monkey sized things. Then saw this.

I hope it's nothing. I am new to the hobby. Been a fresh water aquarium hobbyist for many years and we've just got our own house and convinced the wife to let me get the marine tank I have been wanting for ages.

 

[ncaldwell]

Hard to see but like this?

 

[Ritual]

I'll try and get a clearer picture if he's still out and about when I get home after work. Didn't look like stomatella snail though, the back of it was weird. Before it moved I thought it was a sponge of some kind, it looked soft.

Hard to tell without pictures, I'll probably never see it again now!

 

[Ritual]

Hopefully this is a better picture. He's hiding in the shadows...

The thing right in the middle that looks lighter than the rock.

 

[Rufus’ goofs]

The second picture you posted is of stomatellas. A beneficial and sought after member of a cleanup crew.

It’s a bit difficult for me to tel if that’s what your first picture is of.

I am always looking for them on the rocks at LFS’s and try to get them to sell me them. I can never seem to find anyone intentionally selling them.

If that’s what you have, I count it as a bonus and a freebie. Awesome hitchhiker.

 

[Rufus’ goofs]

Oops, that wasn't you that posted the stomatellas. My mistake.

 

[Ds04384]

Hopefully this is a better picture. He's hiding in the shadows...

The thing right in the middle that looks lighter than the rock.

This looks more like a bivalve, could it be a clam? The can use there foot to move around until they find a good spot to settle down.

 

[LagunaGlide]

Have a look here https://www.lionfishlair.com/hitchhikers-guide/ you may be able to get good comparison photo

 

[Ritual]

Thanks I'll keep hunting and trying to get a decent picture...

 

[Hitman]

I have to agree with it being a bivalve. I had several come in on my live rock when I first set up and I foolishly pulled them all out and put them in the trash now I wish I had them as they are good filter feeders.

 

[Ritual]

I've been continuing to look about at pictures of every kind of hitchhiker's guide and now googling bivalves and I've not seen anything that looks similar to this guy just yet.

I have a magnetic glass cleaner arriving today so I can get rid of the sand residue and bubbles off the glass so I can hopefully get a clearer picture tonight.

He seems to have settled in the shaded spot there, he's not moved in 24 hours so guess he's comfortable.

 

[sfin52]

I hasn’t moved Sounds like a bivalve. They’ll move and settle in at the right spot