Female Anthias wasting away no idea!!!!

[PzReefer]

I have had 7 Anthias squamipinnis in my 110 gallon reef for 10 weeks, and all have been eating well. There are six females and one male all went into the system at the same time. All eat regularly and different types of food. All have grown and have gotten better colour over this period of time, except one female has lost some colour and is wasting away. Her body is definitely not in the same proportion to her head as the others. She hides sometimes and swims with the pack sometimes. she eats ok it seems but still no weight gain. I was lucky enough to catch her sleeping and QT for a weak. In QT she refused to eat at all
so i returned her to the group and two days later now eating again.

Any ideas on what I might try would be appreciated.

Al