Help ID this start fish looking thing

[rpkneumann]

I have no. Lue what this is, it once in a while Shows up on my back wall is the size of a penny.

 

[JohnTheReefer]

Looks like an Asterina Star to me

 

[Uncle99]

Starfish, maybe Asterina, that’s usually what we get.
Some like them, I remove, your choice.
They can multiply real fast.

 

[rpkneumann]

Thank you for the super fast response.
Rather not fight on two fronts at the same time…. battling with a small bubble algae infestation already.
Kind of like the look of this starfish
Do they get bigger?

 

[Screwgunner]

Mithrax crabs.

 

[minus9]

Asterina star, mostly harmless and will consume algae (coralline mostly) and reproduce rapidly. There are a few that eat coral, but that’s usually not the case. Most people remove them, but I don’t consider them to be a pest (some do).

 

[minus9]

For bubble algae, manual removal if you can, then emerald crabs (females) and maybe foxface (50/50) for larger tanks. Keeping nutrients under control is the underlying issue with valonia.