What is in my live rock?? A black starfish?

[Jessica3096]

I just bought about 100 lbs. of live rock and got it set in the tank, and noticed these long black spike covered tentacles curled up in a deep crevice in one of the pieces. What is it and is it harmful to any fish?? The tentacles look like they could be at least 3 inches long. I counted at least 4 of them.

 

[Devilishturtles]

Sounds like a serpent star. Keep an eye on it. If you see the tentacles come out of the hole, particularly at night, my bet is it is definitley a serpent star. They are common hithchikers and usually never move out of the rock, but instead resort to catching food with their tentacles.

I thought I had a picture of one I had hitchhike once, but it must be on the other computer. If I can find it tommorow I'll post it.

 

[Jessica3096]

Yeah, once I turned the white lights off and it was just a dark blue in the tank and everything settled down, it finally started to move its tentacles around. At first I thought it might be dead, but like I said, it started to stick its tentacles out once the bright light was turned off and it was dim. Are they a problem? All I have in the tank right now are snails, a yellow tang, a clown, and a hermit crab.

 

[Devilishturtles]

Nope, they are just harmless filter feeders. No problems.

 

[roka64]

I agree, it sounds like a serpent star. Check out a few of these pics and see if they look similar:
http://www.liveaquaria.com/product/scateg.cfm?pCatId=528

 

[Jessica3096]

It does for the most part look like the pics I've seen of the serpent starfish, but I only see pics of ones that are bright colors. This one is solid black, and second, none of their tentacles seem to be completely covered in "spikes" like the one in my tank.

 

[roka64]

Can you get a pic?

 

[Devilishturtles]

There are about 2,000 or so species of brittle/serpent star so it's nearly impossible to ID the one that you have without a picture, as Roka suggested.

In the meantime, does it look like any of the ones pictured on this website?

http://www.wetwebmedia.com/brittlestars.htm

 

[Jessica3096]

I found some pics on that link that look like it. Thanx :O)
I'll try to find it and take a pic.
He moved out of the rock last night. I barely saw it crawling around the side of the rock into another crack.


Also (it wouldn't let me make a second reply in a row) -- I found one pic in the link you gave me that looks pretty close. It was called a Spiney Brittle Star. How hardy are brittle and serpent starfish? I ask b/c I don't have my tank complete yet and it isn't completely stable. For the most part, all my tests seem ok, there are a few that need to be better though. And I am having a problem with heat in the tank. It has to be pretty cold in the house for the tank to go into the high 70's. Normally, it's between 80 - 81 degrees. Will any of this possibly kill the starfish? And while I'm on the subject, any ideas on how to make the tank more stable and the temperature to stabilize?