What is this in my tank?!?

[Reef.Blue]

Hey guys! I just picked up a piece of live rock for my tank today and found this thing on it. I think it is a brittle star but I don’t know for sure. If it is, are they bad? (I’m sorry I didn’t get a good picture when it was out but I captured a pic of its leg). Please help me out here I just don’t want any pests in my tank.

 

[muzikalmatt]

Yep, definitely a micro brittle star. I had a few hitchhike in on my live rock in my first tank. Love these little guys! They're great members of the clean up crew as they can get into the deeper crevices of the rock where other CUC can't go. You can actually spot feed them too. You'll notice their little tentacles sticking out from the holes in the rock during feeding time.

 

[Mikedawg]

Looks like one; good find and a free cuc member

 

[Reef.Blue]

Yep, definitely a micro brittle star. I had a few hitchhike in on my live rock in my first tank. Love these little guys! They're great members of the clean up crew as they can get into the deeper crevices of the rock where other CUC can't go. You can actually spot feed them too. You'll notice their little tentacles sticking out from the holes in the rock during feeding time.

Thank you!

 

[Reef.Blue]

Looks like one; good find and a free cuc member

How big do they get?

 

[muzikalmatt]

How big do they get?

Not very big at all. Their legs can get to be an inch long, maybe two, and their center body is typically about half the size of a pencil eraser. They stay small so they can hide in the rockwork.

Their population can get quite large though if you feed a lot, particular broadcast feeding as they can catch food from the water column with their legs. At one point I had a ton of them and was pulling them out of my filter floss during every water change, but when I dialed back my feeding their population dwindled. They're much like bristleworms in that their population typically matches your feeding level.

 

[PeterEde]

I have some large bristles in my list of hitch hikers. Hopefully none get too big

 

[Reef.Blue]

Not very big at all. Their legs can get to be an inch long, maybe two, and their center body is typically about half the size of a pencil eraser. They stay small so they can hide in the rockwork.

Their population can get quite large though if you feed a lot, particular broadcast feeding as they can catch food from the water column with their legs. At one point I had a ton of them and was pulling them out of my filter floss during every water change, but when I dialed back my feeding their population dwindled. They're much like bristleworms in that their population typically matches your feeding level.

So would I want to keep or remove them?

 

[muzikalmatt]

So would I want to keep or remove them?

Keep them! Even if their population grows they won't hurt anything. They're a wonderful addition to the clean up crew and they're not something you can typically buy so count yourself lucky that you got one for free!

I actually had people asking to buy some of mine when I had so many because like I said, you typically can't purchase them. (Although, I think there's a guy here on R2R that's selling them now as he's having a similar population explosion.)

 

[EricR]

Micro brittle stars are cool!
I rarely see mine out and about -- just their arms sticking out of rocks at fish feeding time.

*I see them for sale on eBay pretty cheap but that's probably a risky endeavor, in terms of possible fish disease/parasites/etc.

I bought 6 in a ball of chaeto off eBay like a year ago (before I knew any better) -- still going strong and no problems introduced but not sure I'd go that route again.

I've posted this pic of a couple of mine before but I like the pic so (((sorry))):

 

[Reef.Blue]

Micro brittle stars are cool!
I rarely see mine out and about -- just their arms sticking out of rocks at fish feeding time.

*I see them for sale on eBay pretty cheap but that's probably a risky endeavor, in terms of possible fish disease/parasites/etc.

I bought 6 in a ball of chaeto off eBay like a year ago (before I knew any better) -- still going strong and no problems introduced but not sure I'd go that route again.

I've posted this pic of a couple of mine before but I like the pic so (((sorry))):

Thanks!