Brittle Star or Serpent Star Baby?

[LAB]

This little guy must have come home on my live rock, but I just saw him for the first time on Friday evening. He is living in a cave in the rock and came out for the first time when I was feeding my corals. Now that I know where he lives I sometimes see one or two legs hanging out of his cave, but haven't seen him all of the way out again. He is bigger than the end of your pinkie.....probably 3/4" to an 1" and a off white to tan in color. I thought he was probably a baby brittle star, but because he is still so small the coloration does not resemble anything in my invertebrate book. My SIL thinks he may be a serpent star since he is living in the rock rather than in the sand or closer to the bottom. I was hoping someone may be more familiar with this species and help me identify the little guy. I want to make sure that he is getting everything that he needs in the way of care.



Thanks a million!

 

[capncapo]

That is most likely an adult mini brittle star.

 

[The steven liu]

It looks like a serpent star. Brittle stars would have hairier tentacles.

 

[LeslieH]

I love the way reefers use common names - it's so confusing! :rollface: Most people I know use brittle star & serpent star as interchangeable names for anything in the class Ophiuroidea. So you all use serpent stars for ophiuroids with smooth arms & brittle stars for ones with spiny arms?

To identify one of these from images a specialist would require good whole body shots of the top & bottom plus close-up images of various body parts like the arm spines & jaws. If it normally lives in a rock crevice with only the arms outside then it's probably a detritivore or planktivore rather than a predator. It uses its arms to sweep over the rocks & pick up food when there's no current; if there's current it will hold the arms up to get food floating by. What size food it eats depends on the size of the animal.

For more information on ophiuroids in aquarium read this article:
http://www.reefkeeping.com/issues/2004-12/rs/index.php