Wow again. That's some serious start to someone's biography.
I can't say our jaus were that vicious when they were small, I don't think they were but their tanks had been bigger, 120 gal the smallest... but between 1' and 2' they killed plenty of tankmates too in a 500, 1000, and 1500 gal ponds, not every day or week but monthly or every now and then.
In a 120 gal tank, I couldn't keep for long a jau and a TSNxLei hybrid at about 10" each as both attacked each other but jau was winning, if memory serves.
And in our 4500 gal, they are the main culprit behind most damage to their tankmates, and needless to say to themselves too.