Critter ID

[Mhamilton0911]

Hello, new tank with a single live rock newly acquired. This is the first 'critter' I've seen. Any idea what it is? Harmful? Should I remove or leave it? Last picture I have my finger on the outside of the glass for size comparison.

 

[ChiCity]

asternia

 

[Jekyl]

Asterina star fish

 

[dank reefer]

Those are Asterina Starfish and can be harmful to corals depending on the species. I would remove them as they can get out of control

 

[F i s h y]

Astrena starfish. Mixed bag on whether it's good or bad.

 

[Jeffcb]

Asterina star

 

[Just John]

they can multiply into the hundreds. Unless you really like it, you should remove it.

 

[MaxTremors]

Asterina starfish. I would say 95% of the time they are harmless if not beneficial. The white ones (like the one you have) are not the type that eat coral (IME), it’s generally the darker brown and grey ones that will eat coral. They can however multiply quickly if you’re feeding too heavily or if nutrients/algae get out of control. Personally, I would keep it, if their population gets out of control, they’re not hard to manually remove.

 

[Mhamilton0911]

I remember this when I got my first pest freshwater snail. That turned into an outbreak that ultimately resulted in a tank tear down. I still have those pest snails, but i keep thier population down intentionally.

So I'm on the fence here. I'll do more reading. Is there a good resource to identify the species or might be?

Asterina starfish. I would say 95% of the time they are harmless if not beneficial. The white ones (like the one you have) are not the type that eat coral (IME), it’s generally the darker brown and grey ones that will eat coral. They can however multiply quickly if you’re feeding too heavily or if nutrients/algae get out of control. Personally, I would keep it, if their population gets out of control, they’re not hard to manually remove.

I was typing my first response when this posted, so mine seems pretty brown....

 

[Just John]

Just think of what the risks vs the benefits are for you. I think it really comes down to how much like them vs the risk of them having a snail-like infestation.