White / Greay Starfish? ID

[hard10s]

So this guy recently made his way out from within my live rock and I cannot tell or find any info on what it may be. I have historically had a few Asterina starfish, but those are about the size of a penny. Stretched out, this guy is between quarter and half dollar size. He has active tube feet for moving (super slow).

It has 4 legs only and crawled out of my rocks. Any ideas?

 

[Timfish]

Looks like an Aquilonastra starfish, beneficial and feeds on algae and biofilms. Ceck these links for more info:

Good or bad?

I found one of these in my tank when the lights went out crawling on a rock. Anyone know what this is and if it’s good or bad?

www.reef2reef.com

https://museumsvictoria.com.au/media/4094/63_2_oloughlin_rowe.pdf

 

[ISpeakForTheSeas]

Yeah, it may still be an "Asterina" (actually Aquilonastra, as Asterina is a different genus in the same taxonomic family, Asterinidae), as some of the species (while less common in our tanks) get quite large.

It depends on the species - some of them can get up to almost 4" (~10cm). Most common ones in the hobby are tiny, but there are actually a number of Aquilonastra species that get larger than 2cm.

 

[hard10s]

Fun update. It split in half and part receded back into the rocks while the other half is now climbing the glass.

 

[ISpeakForTheSeas]

Fun update. It split in half and part receded back into the rocks while the other half is now climbing the glass.

That is a fun update - love the pic of just the two legs climbing the glass.