Who's eating my lyretails tail fins?

[Scdell]

I have three lyretail anthias. Medium size.
I've had one for about 6 months, about 2 months ago I added three more. Two females and one male. The male didn't make it a day.
Shortly after i added the three the one I had came up with tail fin eaten almost off. It's been doing fine and tail growing back good.
I woke up this am to find one with the tail almost completely gone and another one with 1/4 gone. The other one is a little bit bigger and I can see the tail fin shredded a little bit.
Fish list:
2 percula clowns, pair
1 tomato clown, owns the anemones in the tank
Male and female Lamarks angel. I suspect the male
1 6 line wrasse, I heard they can become agressive. Suspect
3 Blue reef chromis. One has turned male and has gone into seclusion as of late. Doing good, comes out to eat, but seems like he's been bullied
1 chalk bass
2 mated blue devil damsels that have been spawning for a couple years now. Interestingly enough the male was agressive until I put the Lamarks in the tank.
He lost a battle with the male lamarks and was pretty tore up. They settled things between themselves.
I never see one ounce of aggression in the tank besides the usual petty things that go on in a tank. Rare at that.
This is something that happens at night.
The fish I see active at night are the lamarks, the anthias and the wrasse.
I feed 3 times a day. Cuc is various snails and hermit crabs which all are getting low, so I've just ordered more.
I'm leaning to the lamarks with the 6 line wrasse a close second.

 

[Uncle99]

They can be quite mean to their own species.
Adding to a single or group can push others out.

 

[Scdell]

They can be quite mean to their own species.
Adding to a single or group can push others out.

I did think about that too. I thought maybe the bigger one is turning male. There's no, none aggression during the day.

 

[dvgyfresh]

Fish behave differently when your not watching , try to make room dark and very little light on tank to observe

 

[takitaj]

The male doesn't actually bite the females, they just dart at them and chase 'em. I believe it's to keep them from turning. (that's just a guess) I'd bet on the damsels or maybe the clowns.

 

[Uncle99]

In my case it wasn’t the male, it was a female who beat the crap out of another female, and chased her right out of the DT.
And now there is one less, but remaining ones seem settled.

 

[Scdell]

The male doesn't actually bite the females, they just dart at them and chase 'em. I believe it's to keep them from turning. (that's just a guess) I'd bet on the damsels or maybe the clowns.

The pair of clowns stay by the corners of the tank all night. The other clown stays in the anemones all night. Damsels have a "spot" where they spawn. So, unless the anthias are getting into their spot I don't see that either. I'm beginning to think @Uncle99 is right. Aggression from their own species. They'll figure it out.