Those are good general suggestions, but tiger barbs are VERY hard to sex. Especially if they are healthy, because even females can get the coloration of males. While tiger barbs are fun--there isn't much reason for the amature to get into their breeding. Stores are very unlikely to buy them from a local breeder, and they are not high demand fish. They also produce huge spawns, so unless you want a couple hundred tiger barbs, it is better to just buy them from the store.