I keep all three species, but I do not keep them together. In my experience, the festae are the far more aggressive fish. The atro's would be next, and ornatum third on level of aggression. When smaller, the ornatum show conspecific aggression, but not so much with other fish. They become more aggressive when larger, while the festae and atro's will display aggressiveness towards all other fish at smaller sizes.
The ornatum's "shy" behavior is a myth. All will come to the front of the tanks when they see you, awaiting to be fed. All will greedily feed from the surface, and all will accept just about any type of food.
I wouldn't be surprised if it was the atro's that chewed on the ornatum tail. My atro's have done this to at least 3 other fish (chewed on the tails). I found it to be a particularly odd and different behavior. In any event, I hope you have separated the ornatum. You may need to treat with an antibiotic because infection can set in.
I personally would not keep the three together unless they are housed in a very large tank with many hiding spots. I've found the ornatum to be slower growing than both festae and atromaculatum. In my opinion, it will just be a matter of time before the festae rule the tank. Their high degree of aggressiveness, coupled with the large size difference between your fish, and the overall size of your tank may spell trouble in the very near future. I would think that you will soon have to also remove your tigrinus.
Nonetheless they are all great fish.
Edit:
I forgot to add, the more colorful, orange-red atro is the female.
