Something has/is stressing them now. I have no idea what, or what exactly to do. I have a 12g aio tank that I use for qt. If I were to see some strange slime pop up after moving them or a stressful event, I might qt. I'd start with the General Cure meds ,I believe it's API metronidazole/praziquantel. If there were any lesions I'd use the antibiotic- I believe it's erythromycin. If this is Brook you need to use formaldehyde -like Rid-Ich, Formalin-3. I can't tell from the pictures, but really there isn't any meds you can use in a reef tank with coral. You'll have to qt and do daily water changes.