You probably did something to stress it out. When it thinks it's going to die it will let out eggs, which should look kind of like co
ebs. This happened to me and really made my tank look dirty all over, I even had to take my Lionfish out because the "co
ebs" were all caught up in the Lion's fins.
It's really up to you if you want to clean up the mess, but I am pretty sure your inhabitants will clean it for you.
In a couple months you should see little baby featherdusters sprouting around your tank. Congratulations.
Justin