Is this Starfish harmful?

[Fish noob]

I have a 60g cube that's been cycled for about 2 weeks (after a 5 week cycle).

Today I noticed 2 VERY small starfish stuck to the glass. One appears to have six legs, the other 5 legs. They are white and about 1/16" across. What are they? i plan on having a reef tank- what should I do with them?

 

[melosu58]

They are asternia stars. I have many in my tank and they have never caused any problem in the 14 yrs I had them. They will reproduce by dropping a leg and then growing another star from that.

 

[Fish noob]

They are asternia stars. I have many in my tank and they have never caused any problem in the 14 yrs I had them. They will reproduce by dropping a leg and then growing another star from that.

Thanks for your help!