Don't lose hope bro. May still recover. My bubbles had the same experience, and even had 1/3 of the skeleton out and algae grew on them, took a cpuple of weeks to recover, and with proper care, they're still very healthy now. Just make sure water parameters are good, I do target feed them once or twice a week with a little frozen mysis, and avoid high flow areas. As for lighting, mine liked low to medium lighting. And yeah, make sure no fishes are bothering it. Good luck