Agree with Andy, its unfortunate but a group of mean tiger barbs, if you're going to have them at all, are going to do a lot better as -one of the smaller fish- in a huge tank where their group has to kind of stick together and watch out for groups of still larger fish! So we're talking more like 75, 125G or bigger for the situation they work better in. But hey!, fish that look colorful from across the room, like tigers, are not the only type of beauty you can find in a tank. Find a day with some extra time and just go slow and gaze at different types of fish at your LFS.
~~waterdrop~~