Pintail wrasse aggression at night

[150 Gallon Reef]

I have a waterbox 60.2 with a pintail Wrasse, diamond tail flasher, a longnose hawk, orchid dotty, Midas blenny, and a dwarf white spot file. I added the diamond tail about a week ago and I've noticed every night when the lights begin to dim, the pintail turns on the diamond tail flasher and starts to chase him. He has taken a scale or two off of him becuase of it.
The two get along great throughout the entire day, but only during dimming the pintail becomes aggressive. Even when the lights turn completely off and are swimming around, there is no aggression.
Has anybody had any experiences with this happening or know why it happens? I hate to see the diamond tail get beat up for a small period if time.

 

[myzislow]

Super common actually. I'm not sure what the cause is, but aggression increases amongst fairy wrasse when the blues come on. It can be a constant battle for sure. I've kept tons of fairy wrasse over the years and 99% of the time i run into aggression issues are at night when the lights dim down.

I've had fish work it out and have also had situations where removing a rogue fish was absolutely mandatory. A little chasing is fine, but constant harassing to the point one fish is visually stressed is not good.

 

[juliersavage]

I ran across this post trying to figure out what the heck is going on with my blue side fairy wrasse. He is super good all day but about an hour before lights out he gets bent! Thought he might be hangry. Food didn't work. Thought he might need some extra swim room so I was thinking I might move him to my husband's tank but ithen I noticed the nightly pattern and saw this thread. It sounds like his little evening attitude would go right along with him if I moved him. Thanks for the share