Yeh they shed every once and a while. Mine does it about once every few months. but if you start to see it dissolve, then you have problems... Thats why its scary every time it sheds, bc its hard to tell if its sick, or just shedding. Also, get that aiptasia out of there.. where there is one, there are many, and the spread way to fast! Oh and just curious, what are your water specs? check to see that the nitrates are low. stools can be a lil sensitive sometimes.