They start out crazy territorial if given room. The older they get the worse it gets. IF you cram them in they always see eachother and can't get away from eachother. This way no boundries are established, no territories are claimed.
I thought this was total BS myself when I first got them, but after they started shredding eachother I was open to others' opinions. Mad ness and Channarox enlightened me..... They were totally right. It was just like a switch, 40 gallon they play nice, 300 they shredded eachother, 40 they actually healed all the lost scales and shredded fins, back to the 300 and they would chase eachother in circles so fast they would make lil sand tornados.
If you're gonnas try Dorado then don't plan on keeping any other fish you value with them. Mine kicked the crap out of Armatus, Cynos, and Odoes. Did it "work"? If you don't mind a tankfull of ripped up fish then yes, but if you don't enjoy Armatus with 1/2 dorsal fins and fish missing tail fins, then you seperate the Dorado.
As far as working shoals, I'm open to the idea..... Prove it to me. Mine failed just as many others' have.