Creature making a mound of sand

[MTBake]

No idea what is making this pile of sand. Wasn't there yesterday but it's there today. Here's a pic;

I have not seen whatever it is that's making this small pile of sand. I have seen a puff of sand come from near the center of the pile. Kind reminds me of a volcano erupting. Anyone have any ideas what this could be?

No new additions in past 8 weeks. Tank was started with dry rock and sand.

Any ideas before I go terminator on this thing with a siphon hose to find out what it is?

 

[Holy_makerel]

I had a bunch of those structures in my old tank. It was some sort of worm that was making them. Didn't seem to bother anything so i didn't worry about it. When i transfered over to my new system i seeded with some sand from my old but have never had the mounds return.

My conch and sand sifter star may have eaten them all whatever they were

 

[cmcoker]

Spaghetti worms do that in my tank, but it could be something else too.. hard to say
Also called hair worms.

 

[MTBake]

I had a bunch of those structures in my old tank. It was some sort of worm that was making them. Didn't seem to bother anything so i didn't worry about it. When i transfered over to my new system i seeded with some sand from my old but have never had the mounds return.

My conch and sand sifter star may have eaten them all whatever they were

I hope it's ok for the tank. It sure is clean looking sand that's piling up!

 

[MTBake]

Spaghetti worms do that in my tank, but it cdx would be something else too.. hard to say

I do have spaghetti worms in here and have for years. Never seen them pile up sand in this manner myself. Anything is possible.

Could it be medusa worm? I thought I saw a couple on some macro algae that I got. But that was 6 months ago. I removed what I saw at that time but some could have made it into the system

 

[MTBake]

The mound is growing kinda quickly. These two pics are 30 minutes apart

 

[MTBake]

I'm thinking of siphoning this area of sand out of the tank in hopes of catching and identifying this creature. I'm not really worried about it in my tank. Just want to know what it is.

 

[sullyman]

What fish do you have? Anything that burrows, it could be something digging some where else and dumping the debris in a pile. Look after lights out for a while.

 

[MTBake]

Good point! I do have a yellow watchman goby. I looked after lights out and thought I saw some kind of work there. My light scared it back into hiding. Going to try again tonight.

 

[lambchops]

Good point! I do have a yellow watchman goby. I looked after lights out and thought I saw some kind of work there. My light scared it back into hiding. Going to try again tonight.

Do you have a red light?