Lyretails are hard to keep in groups most of the time.
Females turn on each other killing the smallest first and working their way up. They fight to be the next in line to be male. Then there is the issue where the male can be super aggressive and without multiple females to disperse the aggression can kill a single female.
They are hard to keep in multiples. Some people do get away with it especially in larger tanks or tanks with other aggressive fish etc.
Another issue is since they are a aggressive fish adding another to established anthias can be hard.
If one female is larger your female it is most likely turning male. That would be a issue with another male for sure with lyretails.
Want more anthias add another kind. like a single bartletts which is hardy but even worse in groups of its own kind. The nice thing is they also can hold their own against a lyretail most of the time.