In a way, it looks like AEFW with the way the tissue is more pale in certain areas compared to the other but then again it could be that thee frag is just not doing well. I assume you didn't dip your new frag. If you didn't, you take that chance every time. With that being said, buy some CoralRx if you don't have any and start dipping your corals. It can be the difference between a healthy tank and an epidemic.
If you lose the frag because of water chemistry or simply too much stress on the frag itself, that's one thing BUT releasing AEFW or any other parasite is another.
To be 99% safe, QT your new livestock. Yes it's a drag but I have seen countless tanks worth thousands of dollars in SPS colonies alone crumble because they didn't take precautionary measures.
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