Fish at war in QT

[FaithKlim]

20 gal QT, set up in mid Jan, completed cycle a week ago. Bare bottom with hob filter & heater, glass top. Ammonia 0, nitrite 0, nitrate 10.
Added first fish on Thurs 3/22, 3 female lyretail Anthias purchased at LFS. Acclimated well, and ate frozen foods first day & each day since.
Dosed prazipro Sat 3/24. All 3 seem very healthy, good eaters, active swimmers.
Well, tonight I observed 1 chasing the 2nd all over, as well as moments of their mouths "locked"?!? Very aggro behaviour. I tried to distract with feeding to no avail. The war has been happening for a few hours now; in the meantime the 3rd guy is just trying to stay out of the way.
Any advice? These 3 were together at LFS, and the only 3 in that tank. Store guy said they had them around 1-2 weeks...

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[nereefpat]

It might be worth separating them with egg crate.

 

[billdogg]

You may very well have two that are both trying it become male. I would suggest taking one back and getting another, smaller, certainly female. If the two are both going through the change, the aggression won't stop until one of them is dead.