why is my serpent star losing legs?

[kev-dog1]

Came home to two still squirming, unattached legs.
Is this normal?
I got these two extremely spiny black serpent stars in a "clean-up crew" about 18 months ago. I'd had a green serpent before that was very entertaining scurrying for food, but these two just hide under rocks all day... and since getting them I've lost several nice shrimp :( So they are not my favorite tank residents anyway...
But I am curious why they, or maybe just one of them, are losing legs?

Also any hot tips on catching them? Are they nocturnal, coming out in the dark and thereby making themselves easier to catch?

Thanks

[JLouv]

Any starfish will lose their arms when they're stressed.....something is not right with you water or something is harrassing it.....

[kev-dog1]

what harrasses a VERY spiny serpent star? Other tank inhabitants are two clowns, a pseudochromis, CB shrimp and hermits/snails.

[EvilMel]

You may want to check two things: pH and salinity.

I had three starfish, two were huge and one was small. The small one constantly lost his legs and my pH was fluctuating wildly (7.75-8.4). So that was decided as a probable reason. Then I have also heard that if you wait a few days to top off your water (something I am also guilty of) and your salinity changes alot when you add Freshwater back in, they can be very stressed.

Also I believe the smaller ones are more sensitive to fluctuations. Not really anything scientific, but just emperically determined by me noticing that my two larger ones didn't seem to have any problems but my smaller one did.

Oh and now my pH isn't fluctuating as much (~8-8.3), woo hoo.

I do agree that it's probably something with your tank parameters.

Mel

[fishdoc11]

Starfish and serpent stars are VERY sensitive to changes in SG. Ophicoma stars(which it sounds like you have)are normally harmless to almost all tank inhabitants and are very usefull as detrivores. Pseudochromis however are not. What type of dottyback do you have? I suspect he may be the cause of the dissapearing shrimp and the stressed brittle star. That or water parameters.
Chris

[fishdoc11]

Btw I also had a CB shrimp that killed three scarlet cleaners before I caught him in the act.

[kev-dog1]

THanks fishdoc & evilmel
I'll check my params. That is something that I've let slide, I was religious about it when I first started in this hobby, keeping a journal and all. But lately...

I've got a neon dottyback/pseudochromis. Dont know the scientific name. Orange with neon blue down the back. He's definitely a piece o' work :) When I do the big tank redo, he's going in the FOWLR with the other demons. I doubt I could catch with without tearing the tank apart. That'll happen when we remodel.

So Fishdoc...can different species of shrimp co-exist?

[fishdoc11]

You have Pseudochromis aldabraensis. They are terrors. According to Scott Michael "It may attack and even disembowel tankmates of smaller or equal size" also "Will eat ....ornamental shrimps"(2001). I've had a peppermint and scarlet cleaner in my 75 for 1.5 yrs with no problems. I'm sure others can co exist also.
Chris

[reewik]

I have a coral banded and a cleaner together with no problems. I have even seen cleaner , sexy, and cb shimp all together. If you have a yellow tang I hear they will pick on the sexy. I do not know I have a yellow and did not want to try it.