Fish turned hostile!!!

[rusty idaho]

I have a mostly docile tank.
3 clowns
YWG
3 pj cardinal
Raspberry dotty
File fish
Purple fire fish
Tomini tang
4 blue green chromis

My wife picked out a bicolored dotty and we added it to the tank. I thought there might be an initial issue with the other dotty. I was shocked when the whole tank responded like a frenzy of piranhas!!! The only fish that didnt harass the new dotty was the cardinals and file fish. Everyone else just beat the crap outta the bicolor!!! Even the purple fire and the YWG!!! They constantly chased him down! It was sad.
Has anyone else ever experienced this?

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[kartz09]

Could the fish possibly be sick and the others some how know that? I recently got a two spotted tang and my Midas blenny was attacking him, I put a mirror up to the tank for a day, the blenny started fighting himself and allowed the tang to get comfortable


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[rusty idaho]

Possibly??? It was just strange. My purple fire fish never harrased anything before. I was thinking that possibly the fish think that their reef is "full" and no room for newcomers???

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[Diana A]

what size is your tank?

 

[rusty idaho]

90 gal with 30 gal sump
About 35 lbs of live rock.


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[jaybfresh]

That's a lot of fish for a 90, and the tang, clowns, and dottyback are not docile fish. I'd guess there's just no more open territory left.