170 will probablly be a lot better. When I had my group in a 125 they were fantastic until around 4 inches, then they started getting territorial. The dominant fish would patrol the entire tank and chase any other archer into the back corners behind the plants. So then the other archers started fighting for their each little hiding spot. No damage was actually done to the other archers but only the dominant fish would come out and eat. I lost two to stress and no food before I decided to just rehome everyone. That was actually why I left the hobby for three years, it pissed me off so much. Anyway, the little info I found three years ago, regarding wild populations is that, they don't appear to school as much as other archers when they get larger. That was my experience, I think I just needed a lot more space for them though, I'm curious to see how yours are doing three months from now