My Anenome does fine with stable ALK. High ALK or jump of it is instant death in my experience. Plus WC don't pour the water on top or near them. Looks really bad, only thing to do is figure out what happened to learn from it and wait it out and see if it will rebound.
@yassir999 what are the params, are they getting enough flow, are you target feeding daily and broadcast feeding 3x a day everytime u feed the fish, could be high or low alk, or a bacterial in fection a rock of yumas did this to me a while back you can either try cipro antibiotic dip or moving rock and placing it in a higher spot medium high light area with a little more flow just be careful not to blast it to hard, you can also feed freeze dried brine shrimp soaked in selcon to fatten them up