Stars with 6 legs in seawater aquarium

[DrDu]

Recently I visited a sea water aquarium with tropical fish anemona, corals. At the glas walls I observed little (about 1 cm diameter) white stars with 6 legs.
Now starfish have 5 legs, as far as I know.
Any idea what this could have been?

 

[Borek]

Googling for hexaradial starfish finds this page:

http://www.wetwebmedia.com/ca/volume_1/cav1i4/echinoderms/echinoderms.htm

Scroll down to the green table. No idea about the site credibility, but at least it gives some ideas about what to look for.

 

[jim mcnamara]

Sea stars mostly have 5 "arms" or "legs". Some have more - up to 40 arms.
The sun star can have 40:

http://0.tqn.com/d/marinelife/1/0/C/5/-/-/Sunflowerstar-500x3750-Patrickbriggsflickr.jpg

 

[mishrashubham]

Googling for hexaradial starfish finds this page:

http://www.wetwebmedia.com/ca/volume_1/cav1i4/echinoderms/echinoderms.htm

Scroll down to the green table. No idea about the site credibility, but at least it gives some ideas about what to look for.

The site seems pretty reliable and as far as I know (about echinoderms), the information provided is correct.

 

[DrDu]

Thank you all very much for the info. I didn't know that there is so much variability in the number of arms in starfish. The ones I saw resembled very much Asterina species which are described in several aquaristic forums, like here:
http://reefkeepingfever.com/forum/forum_posts.asp?TID=12