In my experience tuba are generally very hard on each other, even as juvies. I started with half dozen 2" juvies in a 150 gal tank, and from the get go, they were relentless. Ended up with the 3 males, that were given to Dr Mike who had the "Black Widow"female.
My water flow/current was approx 1200gph at the time, and in retrospect it should have been double that, and temp may have been a bit high 80'F. More current and lower temp may have made aggression less, but they shared the tank with 6 Paretroplus menerambo (which they ignored).
I am keeping the seiboldi and asfraci in the mid 70s now with high current, and aggression seems relatively minimal so far, all are small yet though (2"-4").
