The Sinularia in question. Has been closed up for around 2 weeks. Had some light black growing on the tips. I gave it a 30 min iodine bath and brushed it gently with a toothbrush to dislodge any algae or growth. In the past 3 or 4 days it has started becoming wrinkled on the left side as in the pic. That was before the bath. I am not sure if this is normal behavior or if the coral started out shedding but then became infected. Had a gallbladder attack last week so maintenance hasn't been super thorough lately - I attribute it to a reduction in flow, but I'm not sure. I've since soaked both Nero pumps and flow is back to being much more robust.
I had a peppermint shrimp and a tang that was picking algae off of it after it first closed up so idk if the tang or peppermint contributed. Everything else in the tank is doing great (mixed reef; lots of acros, torches, another leather, montis, zoas, alveopora etc) so I don't *think* it's a parameter issue. This is the second sinularia that has done this for me. Is it a goner?
Idk if this is relevant but it feels very hard in spots (though it could be because it's contracted; it was easily 3 times this size open).