6 Legged starfish?

[cinder]

I have seen this several times crawling up the back of my tank. The first time I looked at it, I thought - that starfish looks a bit strange

Apologies if this is a dumb question, but does anyone know what this is? It is about 1cm (0.4 inch) across.

Thanks

 

[charlesr1958]

I would think a species of asterina, most are harmless yet there are some that can be a problem in a reef tank, would just keep an eye on it for any predatory tendancies towards corals.

 

[LeslieH]

Did you notice the size difference between the top legs & the others? It's regenerating the bottom ones.

 

[charlesr1958]

From what I have seen of asterinas, that seems to be a given, they must be very clumsy or very unlucky...lol, dont think I have seen one yet that didnt have at least one odd ball length arm. Either that or its a genetic trait?

 

[narow37]

the reason that you usually see them with odd length legs is because the reproduce by splitting in two and then regenerate what was split off.

 

[tinysuperbug]

Yep, asterina, splits a lot, often hasmore than five legs.

 

[cinder]

Thanks for your help I see that I not only demonstrated my ignorance of invertebrate biology - but my inability to count as well On recounting I see it actually has 7 legs!