What is this?

[Gtojr]

Changing out an old tank to start a new reef today. When I took the old rock out to put in live sand, I found this thing.  I’m trying to upload a picture but it’s about an inch long, fleshy, grey, eggplant shape.  At first I thought it was a plant but now it’s extending and contracting a “tail” or appendage. Any clue to what it is? 

Editing to also ask about spongy things on bottom of a few rocks. Are these the sponges that I am reading I should remove with a tooth brush and rinse with old aquarium water, then replace in tank? 

[Solga]

I will be tagging along, just to see what this ... "thing" is.  At first glance, I thought it may be a sea cucumber of sorts, but after looking a little harder, I really have no clue.  I wish I could help with the ID tho.

No idea about the sponge either.  My phone doesn't show pictures very well with it's 4 year old scratched up screen. 

 

Adam

[WV Reefer]

1 hour ago, Gtojr said:

Changing out an old tank to start a new reef today. When I took the old rock out to put in live sand, I found this thing.  I’m trying to upload a picture but it’s about an inch long, fleshy, grey, eggplant shape.  At first I thought it was a plant but now it’s extending and contracting a “tail” or appendage. Any clue to what it is? 

Editing to also ask about spongy things on bottom of a few rocks. Are these the sponges that I am reading I should remove with a tooth brush and rinse with old aquarium water, then replace in tank? 

Peanut worm. Good guy to have. 

[Gtojr]

Really? I can put him back in? He’s currently quarantined, 😆 I can’t believe it’s actually a

good thing for once! 
 

can you tell I’d the first picture is a “pineapple sponge”? Actually reading here that is a good thing also?

[WV Reefer]

3 minutes ago, Gtojr said:

Really? I can put him back in? He’s currently quarantined, 😆 I can’t believe it’s actually a

good thing for once! 
 

can you tell I’d the first picture is a “pineapple sponge”? Actually reading here that is a good thing also?

Both are very good things. 😊

[Gtojr]

Thanks so much!!!

[jcrisman2009]

On 10/17/2021 at 8:05 PM, Gtojr said:

Changing out an old tank to start a new reef today. When I took the old rock out to put in live sand, I found this thing.  I’m trying to upload a picture but it’s about an inch long, fleshy, grey, eggplant shape.  At first I thought it was a plant but now it’s extending and contracting a “tail” or appendage. Any clue to what it is? 

Editing to also ask about spongy things on bottom of a few rocks. Are these the sponges that I am reading I should remove with a tooth brush and rinse with old aquarium water, then replace in tank? 

Peanut worm. Detritus eater very beneficial.