They squabble with anything that's silver, shiny and looks sort of like them. That's part of the reason I keep barbs with them; if there were tigers in there by themselves, they would beat the hell out of each other. With the barbs in the tank, the two tigers still squabble among themselves some, but with the dither fish in there they actually school together and pick on the barbs. They fought for a few days to establish dominance (hence the shredded tail on the vittatus), but since they've established a pecking order it's been ok.
A couple of days ago I put the TATF in my big tank because well, I just didn't realize how big my big fish were. The TATF is 5.25 inches long now so I figured he was big enough to make the move. He wasn't so I moved him back. But I digress; the point I'm getting to is that when I put the TATF in the big tank, he spazzed like you'd have expected him to. The payaras especially scared him. They didn't bother him, but they scared him lol. He was zipping all over the tank till he found Max the goliath. When he found Max, he calmed right down and fell in to shoaling behavior with him and was calm. He followed Max everywhere. I thought it was cool. I actually watched him in the tank under very close supervision for about ten minutes before I took him back out and moved him back.
But I'm rambling.
A direct answer to your question is that they will always have their scrapes, but if they have silvery similar looking dithers they can gang up on they seem to do better. Accidents can always happen though, and with the weapons these guys have, they make their accidents count. My method is to have enough dithers to try to keep the accidents restricted to my cheap fish, not my expensive ones.
