I have to agree with all the comments re: barbs in community tanks. I have a species tank with several varieties of barb. One word of warning that I have learned the hard way: Barbs are extremely curious fish and when I first set up the species tank (120L) I introduced a rock with a number of crevices etc. Unfortunately one of the more curious barbs managed to wedge himself in a barb-size hole. This was a most distressing experience. Now I have smooth rocks and drift wood and have the tank heavily planted with interspersed swimming areas. Barbs are great fish and most of them are enthusiastic clowns of the aquarium world. I heartily recommend them!
I have a school of 12 barbs in a 55 gallon tank. I love the way they school together but they kill every other fish I put in with them. I would recommend to keep the schools of barbs between 5-9 fish of equal size. When there are too few fish they are agressive and as I found out when there are too many barbs they are also agressive.
I have only limited experience with this fish, but I notice that they are really friskie creatures. The male (who is really really beautiful) is always chasing the females.
The tiger barb has been a good choice since the beginning of aquaria time. It is such a spastic fish, especially when it is young. It is a medium docile fish and is a fish lover's fevered friend. I love the fish, it ads a river touch to my fresh water tank. All around it is a great fish for beginners.
I have a 200 Liter Tank, in there I have 1 tiger barb, angel fish, albino barbs, a green barb and some assorted tetras. I have found that if you have barbs in with other barbs, they will play around with their own species and leave every thing else alone.
I was given a 200 L tank with five large Köi and just purchased two Tiger Barbs and a Black Molly. One Barb is very docile and the other chased and nipped relentlessly at his pal and the other fish who were 10 times his size. Although I admired his bravery, for the Köi could have swollowed him whole, I had to return him to the store. The shop owner suggested I try another as their personalities vary. As it seems so far the new guy likes to nip as well. I could now do two things, add two more Barbs and see if this relieves the problem as suggested they do better in schools, OR just keep the one docile Barb. Not sure how this will affect him though. I hate to give them up, they add great color to the tank but I also would like the peace kept.