Green Brittle Star--Crab killer?

[Sniper308]

Could anyone please tell me what exactly green britle stars will eat. I feed him with plankton tabs and other sinking prepared foods but have noticed some mysterious dissappearances since his addition about 2 weeks ago. In two weeks I am missing an anemone crab(porcelin Crab) and a fire shrimp. Also believed to be on the missing list is a small sally lightfoot crab. Please advise. Have I added a serial killer to my tank or what?

 

[allenfrenchy]

The vast majority of brittle stars and serpent stars (brittle=spiny, serpent=smooth) are reef safe. The green serpent star is the exception as it is predatory. It catches prey by elevating it's body forming a trap with it's legs. This then looks like a safe crevice under a rock. When a small fish or other prey travels under the star it closes around it and eats it. There have been many reports of small fish diasppearances due to green serpent stars, and I would suspect they could also kill crabs and shrimp. Sorry for the bad news.
Allen

 

[MontanaRocknReefer]

Green Brittle Star getting a bad rap as usual. I also wondered about fish disappearing but have since changed my attitude on them.
If you keep them well fed you should not have any problems. I have a large green brittle star and it is a beautiful specimen. I feed it frozen brine shrimp, flake food, fresh scallop, shrimp, clam and spirulina discs(100% vegetable matter) and it is happy and well fed and have no inverts or fish disappearing for quite some time. JMO Johnny

 

[Sniper308]

I have recently observed what I believe is the action described above by allenfrenchy. I observed the Brittle star elevated with its legs forming what I'll call a bird cage and waiting under a piece of rock. I do not know if I have ever whitnessed this action or just did not associate it with a hunting style. Its something to thank about. I will try to oberve him more closely for the next week or so and report back any findings I may observe.

 

[kjb]

FWIW - I don't know about the trapping bit, but I had one once and swear it was responsible for a few snail deaths. The shells were found near his hang-out completely empty every few days. After I moved him to the sump the mysterious deaths stopped.

 

[ophiuroid]

How big is the brittle???

What other things live in the tank???

Crabs are a primary predator of brittlestars. He might have eaten the shrimp, but I would be surprised if he got the crabs (unless he is a freakin' huge brittlestar, or the crabs particularly small).

It is very likely that he ate the snails, as I have heard this often.

Basically, one must look at the goings on in a tank rather philosphically, and try to remove the impact of the prices of the animals that are missing.

We have tried to build a natural system, and part of that is a food chain. Basically, if he ate the shrimp/crabs/snails, he was hungry. You need to increase the amount/frequency that you feed him. As Johnny said, go for something big and meaty, like shrimp, frozen fish, etc (something that will take some time to digest). Shrimp pellets are popular for the little ones, in addition to other foods.

PS. Johnny...thanks for the previous emails (it was you, right??). Been horribly busy in recent weeks. Haven't sent much email at all.

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Brittlestars!! http://home.att.net/~ophiuroid
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[Sniper308]

Thanks for the comments OPHIUROID. The brittlestar is approx. 10-12" from leg tip to leg tip. I observed him earlier in his hunting pose messing with a red legged hermit that was walking beneath him. He seemed interested and collapsed on the crab only to run off and hide a few seconds later. I think I need to get him out of there. It is such a shame though as he is a beautifl specimen with grey/black markings on his body and his legs covered in black and yellow bristsles. He is also a great scavenger of leftover food and waste as this was the main reason I had introduced him to the tank. I am also starting to doubt the reef safeness of my arrow crab as he has grown quite large in the past few months being just as large if not larger than the brittle star. The arrow crab was origionaly introduced to take care of a large number of bristle worms inhabiting my tank after my live rock was purchased from a LFS. I have seen no bristle worms in the past at least 3 months and as I said think that he may also be on the need to be removed list. Any thoughts from other reefers would be greatly appreciated.

 

[MontanaRocknReefer]

Yes it was me!! Great site you have! For those of you who want to learn about green brittle stars check out her site. Johnny