I wouldn't recommend mixing them, but as long as the Angelfish have some shelter they should be ok. I have 2 large Angels with 14 Tigers and occasionally the Tigers chase them. If the Angelfish were small, then there could be problems. The more Tiger barbs, the less aggression towards the Anglefish. I would say at least 6 would be good.If I knew then what I know now, I probably wouldn't of mixed them.