I agree. Looks like an unhappy BTA to me too. They lose their bubbles for many reasons, sometimes it's unclear/unknown. Many times under less than ideal lighting they will, or when hosted by clownfish. At least it's not bleached out, it should do fine w/ good water/lighting/acclimation. How long have you had it?that look like this after the lfs has had them for a couple weeks. So I say it's just an unhealthy bta.