Geyser of detritus ?

[j.falk]

I've seen this happen quite a few times lately and I have no clue what is going on?

It looks like a geyser of detritus that forcibly shoots out of the live rock several times per day. I've seen it, my wife has noticed it...but we have no clue what is doing it? I know there is either a pistol shrimp or a mantis shrimp in the tank. We can hear the popping sounds throughout the day...BUT...when the geyser happens, we do not hear a popping noise while it's happening.

Any ideas on what might be doing it?

I've also come to the conclusion that there is a portal inside of one of the live rock pieces. I say this because I bought 10 lbs. of live base rock from KP Aquatics...I kept 5 lbs. for myself and gave the rest to a friend. 5 lbs. is not a lot of rock...but for the past 2 months, I've found all kinds of hitchhikers coming out of this rock. Way MORE than I've ever had come in with live ocean rock before...hence why I think there is a portal inside of one of the rocks that leads back to the ocean.

Here is a list of all of the hitchhikers I have found in this 5 lbs. of rock:

- 1 Gorilla Crab
- 4 Pistol Shrimp
- 2 Brittle Stars
- 1 Scallop
- 3 Giant Bristle Worms
- 1 Fleshy Limpet
- 1 Massive Polyclad Flatworm
- 1 Frilly Sea Slug

I feel like every week something new is coming out of this rock!

 

[ISpeakForTheSeas]

Any ideas on what might be doing it?

Based on the description, either something digging into the rock and trying to clear gunk out of it's burrow, or a filter feeder trying to get rid of the detritus (tunicates do this in the manner described below):

The closing (or "squirting") reaction basically happens when specific cells (called coronal cells) inside the oral siphon register particles in the water being filtered that could potentially harm the tunicate. To prevent harm, the tunicate shuts off the siphon (closes and cuts off the water flow) and contracts to squirt the potentially harmful particles out.