Brittle Starfish

[Coasting]

Do you have fish in there?
Might be more of a nutrient problem if there are too many. Excess food = more reproduction.
I found my tank went in waves. Excess pods, then brittle stars, then bristle worms, then astrea or whatever stars by the hundreds now nothing because the wrasses eat everything and the tanks got mostly new rock.

I think if you got a harlequin you would end up feeding it other stars pretty quickly as i hear they eat out food supply quite quickly.