Are these good or bad?

[Firecapt34]

Set up a new aquarium and bought live rock, not sure what these are and if they are good bad or what.

 

[rrspike]

2nd is a asrerina star fish , some say good, some say bad . Me personally I remove any if found.

 

[Caseyoidae]

Second is an asterina starfish. 1st is scary looking. I’d ditch it lol

 

[AcroNem]

I'm actually unsure on the first. I would just let it be, it'll likely just become a snack for a fish
As for the second, the facts are that they used to be in the Genus Asterina, but have been changed to Aquilonastra. Everyone still uses their former name though. There are 28 species and almost all of them are harmless, there are a couple species that can harm corals/invertebrates but we rarely see those in the hobby. They get a bad reputation from the few horror stories and their rapid reproduction.

 

[rrspike]

I'm actually unsure on the first. I would just let it be, it'll likely just become a snack for a fish
As for the second, the facts are that they used to be in the Genus Asterina, but have been changed to Aquilonastra. Everyone still uses their former name though. There are 28 species and almost all of them are harmless, there are a couple species that can harm corals/invertebrates but we rarely see those in the hobby. They get a bad reputation from the few horror stories and their rapid reproduction.

Thanks learned something new . I've been told to pay attention to coloration as it indicates what they are eating. Darker colored = coral munchers. Maybe you can confirm this ?

 

[AcroNem]

Thanks learned something new . I've been told to pay attention to coloration as it indicates what they are eating. Darker colored = coral munchers. Maybe you can confirm this ?

I cannot, and it's unlikely that anyone on here could, unless we have someone who actively works with them. There are some very brightly-colored species that I would personally love to get one day in hopes of testing these things out. From what I've seen, the ones actually consuming coral have had more color on them as opposed to the white,gray, tan we usually see. But that's just not accurate enough to say that the assumption is true or not. I've had plenty with more reds or blacks on them that were harmless.

 

[Flippers4pups]

Completely anecdotal, ones eating diatoms for me turn dark, ones eating film algae are white. Never seen any eat any coral.

 

[Cwentz758]

I can tell you it’s not worth finding out. I’m currently removing them. They’ve destroyed my large rock of GSP they slowly attach and eat the coralline feet until they fall off. I’ve removed over 50 today and I have no idea how many yesterday before my take down and RIP clean. Mine seem to have red dots.