can a tiger barb take out a section of fin like this?

[Deadeye]

i assume when a tiger barb singles itself off and starts breathing heavy its being picked on? i almost never see any aggressive behavior but one or two will do that every once in a while sometimes they bounce back a day later. should i not see any of this behavior and when that behavior goes away is it an indication that the group is finally big enough?

I’ve never managed to keep tigers in a school large enough, but that is the behavior I’ve noticed. When that stops happening you can probably assume the aggression is spread out enough.