Who is attacking my flasher wrasse?

[Phlynamjax]

Hello,

I have this diamond tail flasher wrasse that I had for about 1.5 years. He is fat and healthy. One day I woke up and went check my tank and he was hiding. When he came out, he was terribly beat up. His fins were torned up and missing alot of scale. I quickly put him in acclimation box and he recovered nicely. After few weeks, I released him back to the tank. I did not see any aggression from my other fishes. But one day I woke up to check on my tank and he was hiding again. It was samething. He was terribly beat up. I repeated this process about three times and still can't figure out who is attacking him. During the day when I have lights on, I see zero aggression from my other fishes. My Diamond tail swims happily and eats like pig. Today it happened again and he is back in the acclimation box. Is there anyway to find out who is attacking him so I can get rid of them? All fishes in the tank are at least 1 years old. His current tank mates are:
2 x Bandit angels
2 x Regal Angels
1 x Lineatus wrasse
1 x Golden Rhomboid Wrasse
1 x Pin Tail Wrasse
1 x Pink Margin Wrasse
1 x Saddleback butterfly
1 x Leopard wrasse
1 x Black Leopard wrasse
1 x Helfrichi Firefish

 

[Justanano]

Can't see anyone attacking him from here

 

[9975]

Watch from a distance or set up a webcam of some sort. We have to be at least 10' away from the tank and nobody moving for our fish to act "normal". Whatever the heck that is....

 

[malacoda]

My first suspicion would be one of the fairy wrasses since they occupy similar niches ... and could see the flasher as fairly direct competition. Especially if one of the fairies is ... or has just ... matured into a dominant adult male. (Actually, unless you have a pretty large tank, I'm surprised the lineatus and pink margin fairies get along with each other considering that they're both from the same Cirrhilabrus complex.)

Can you set up you phone on a counter or table to record video when you're not in the room... or with a dim room light on in the first part of the evening after you go to bed ... to see if you can catch the culprit on video?