striped Brittle Star and Seriatopora

[bwells]

I have had one green Birds Nest Coral die of what I think was Slow Tissue Necrosis. It gradually whitened from the bottom up. I was too late taking a frag so that was lost. My 2nd Birds Nest has started showing white at the base and up to the middle. But I did take frags of this that seem to be getting along okay. What I noticed this morning was my Birds Nest had 5 very small striped brittle starfish on the coral branches. As soon as the light comes up, they hide. These stars are between dime size and quarter size. I saw them on the first Birds Nest that I lost.

I could not find anything written that said these tiny brittle starfish are dangerous for my reef. Now I wonder if they could be eating the pollyps on my coral. None of my other corals show any signs of damage and I never see the stars on the other corals I have (SPS, LPS and soft).

Can someone tell me if these starfish are dangerous and if so, how can I get rid of them? Or are they safe clean up crew like other starfish?

Thanks

 

[philosophile]

They're probably eating the algae that is growing on the dead coral skeleton.

They're all over my tank and just part of the clean up crew.

 

[MondoBongo]

They're probably eating the algae that is growing on the dead coral skeleton.

They're all over my tank and just part of the clean up crew.

+1 to this.

my first suspect in the demise of corals, especially SPS, is generally water chemistry. alkalinity/magnesium/pH/calcium being at the top of the list.

second is fluctuations in temperature or salinity.

 

[bwells]

Thanks. I had hoped this was the case. Yes, I had an increase in Magnesium that I did not control quickly enough. Other chemistry has been stable. The good things is that my other 22 species of coral are still thriving. It is just the birds nest that have failed. I will keep being happy to have those brittle stars and probably try another birds nest. The sad things is, they started out the size of golf balls, and by the time I lost them (a year later), each was bigger than a softball. They were really full with complex branching.

Thanks for your advice!

 

[MondoBongo]

You know sertiapora has never done well in my tank. I've had both sertiapora histrix and another sertiapora sp. That was labeled as "sour apple" die on me. Yet my LPS and several different types of acropora spp. Do quite well. I hate to write it off as "every tank is different" but sometimes that just seems to be the case.