Tentacles??

[mr_o98]

I have been watching my tank about an hour after the Halides go out, and the moonlight comes on. I have noticed long grey "tentacles" with black rings coming out of one of my rocks. I have only seen this on one rock. I have seen two of these feeling around the top of the rock, and I have seen two more coming out of the side of the rock and extending into the sand bed. These "tentacles" are around an inch in length. Whenever I would shine a flashlight on them, they would retract into the rock. Does anyone know what they are? Are they good or bad, etc.? Thanks.

 

[capncapo]

Could be a mini brittle star. If it is, they are harmless.

 

[LeslieH]

Sounds like the feeding appendages found in a couple of groups of polychaetes (= bristle worms) like spionids & chaetopterids. Harmless detritivores helping to keep your tank clean.

 

[Lev F.]

Sounds like a Peanut Worm.

 

[LeslieH]

Peanut worms normally have a ring of short tentacles. If there's only 2 thin tentacles per hole then it's a polychaete.

 

[kjmst29]

I also have the "tentacles". I think it is a brittle star.

 

[bertoni]

The mini-brittle-stars do look fairly "antenna"-like. If tentacles are spikey, like a brittle star, that could be what you have.

 

[mr_o98]

there is only 1 tentacle per hole, and they are spread out over the rock. There is at least 3-4 inches between each tentacle.

 

[bertoni]

Hmm, I think I'd need a picture to say anything.