Sand sifting star question

[t11t5]

I have 2 sand sifting stars in a 150g. I always see them on top of each other. What are they doing?

 

[FOSELONE]

tickling eachother

 

[greenbean36191]

Most likely you're seeing pseudocopulation. Their eggs are still fertilized externally, but the stars come together to release them to increase their chances of successful fertilization. Don't expect anything to come from the pairing though.

 

[nreefer]

I have been thinking of adding a sand sifting star to my tank but have been told they will kill/eat everything in the sand bed (making it usless) and then die themselves. Is this true? My tank is a 400 gal and I would like to try and keep the sandbed turned over more frequently. Starting to get some nasties when I disturb it.
BTW it is only 2.5 inches deep.
I have lots of tigertail cukes and snails but the gravel is never really white.
Thoughts?

 

[J. Montgomery]

I'd think that 400gallon would be able to support a single sand sifting star. They don't bury themselves very deep, so 2.5" should be sufficient.

 

[nreefer]

Thanks for the response, I have seen a few large systems with the sand sifting stars on RC. Most notabley the large thread on the guy who switched to T5 lighting. In one of the pics there are a few sand sifting stars, and the gravel is very white.
My hope is since the system has a 300 gallon sump attached with a 2 inch sand bed that will take care of the denitrification and since the my main tank is so large hopefully the critters in the sand bed will reproduce faster than the star will eat them.

 

[t11t5]

Since i bought the 2 I have the sandbed is much hiter than before. I also noticed alot more air bubbles under the sand against the glass.

 

[t11t5]

Just thought I would show you them...

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[/IMG]

 

[nreefer]

Thanks for the pictures. Why do you think there are more bubbles coming from the sand bed? Do you think the sand bed is more productive now?
Also I read in a book that the Sand sifting stars can eat cucumbers? Is this true?

 

[t11t5]

I am not sure if they eat cukes or not. All I know is they helped my sand bed look cleaner. Im happy about that.

 

[leggy]

I would go with several Nassarius vibex - which will keep you sand nicely turned over ..... if you have plenty of pods twinspot gobies would really appreciate them and also keep your substrate nice and clean.

 

[t11t5]

I have around 25 Nassarius snails also. I gave up on gobies. They always seem to jump out of my tank. So Im better off without one. Thanks for the advice.