What could it be??

[kiharaconn]

I have a pico tank on my nightstand right now. I will be setting up my 75g hopefully next week. The only thing in my pico is ls, lr, feather duster and some polyps and mushrooms. As hitchhikers, there are a few baby sails and a couple of small bristle worms and a small astrena star. Well my questions is -- there is something in there that keeps shifting the sand. One day there will be a huge mound in the front of the tank and a couple of weeks later the mound has moved to the back of the tank. I haven't seen anything large in there that I would have thought could do this. Any ideas on what it might be?

 

[jacksdad]

Could be a cucumber. I have one that stays buried in the sand, although it doesn't move much. And I can't remember the last time I've seen it so who knows how big it is.
Just a thought.
Bob

 

[reefnut]

It's hard to say but my pistol shrimp does that... as he digs out and builds his home under the rocks he will move the sand all over. Have you noticed any holes under the rocks??
If curiosity gets the best of you... as it usually does me... watch the tank at night with a red light. You may be able to see it come out. You could also move the "mound" of sand around to see if anything is buried under it.

 

[tuningvis]

i'd just tear up thee sand with a net searching for whatever it was... curiosity would REALLY get the best of me

 

[gfk]

i have a big peanut worm that makes mounds sometimes