Tiger barb trouble

[Fish-mates]

I moved 2 tiger barbs with tails nipped down to stumps from the tiger barb tank into a community tank where their tails have slowly regrown. Should I wait for their tails to fully grow before trying to put them back in the tiger barb tank or should I leave them where they are - even though it's a bit overstocked?

 

[Fishmanic]

How many tiger barbs in the tiger barb tank including these two? Generally, you should have at least 6 in the group to minimize aggression.

 

[Byron]

The Tiger Barb is one of the species of shoaling fish that needs more of them than most species. No less than eight, but ten or more will be safer. And this means at least a 30g tank for the group of 10+. Anything less, and you are almost certain to see problems within the group. These still may occur, as this is a natural behaviour of this species, and there is always the chance that you have one or more especially aggressive fish in the group. And a fish that becomes a bully will not change its habits.

Byron.

 

[Fish-mates]

Thanks for replying.
When I realised the problem I identified the 3 main 'bullies', (all green tigers which I'd thought were more placid!), and took them back to the LFS. I currently have 9 tiger barbs left in a 30 gallon and they all seem to get on pretty well having removed the 4 badly bitten tiger barbs.
2 tiger barbs were taken out 5 weeks ago and after a time in QT are now in with gold barbs and rummynose tetras. The other 2 tiger barbs are still in the QT as the tails have quite a way to go. My concern is unless the tails are all fully grown when I put them back with the other tiger barbs they might remember them and start the harrassing again.

 

[Byron]

Generally, your are fine with the group of 9+ in the 30g, so that is good. I would not leave the two in the community tank for long, as without the others they could start showing their colours as it were, and this is highly stressful to other species even if no actual physical interaction occurs. When shoaling fish are in too small a group, like 2, 3, 4 etc, they do experience stress because of this, and studies have now proven that increased aggression is the normal response in such situations. Personally I would be more concerned for the "peaceful" fish with the two barbs in their midst than I would for the two barbs going back "home."

 

[Fish-mates]

My focus has been letting the nibbled tiger barbs tails grow so it hadn't occurred to me they could be stressed in the quieter community tank by not being with their own. Or equally the tiger barbs presence could be unsettling others. I think I'll keep my eye on them and transfer them sooner rather than later. Thank you Byron, very interesting.