If she is pregnant and ends up laying eggs and you want to try and get some fry you will need to separate the eggs. Tiger barbs don’t make the best parents and they’ll eat the eggs. I’m assuming you have a school? It’s very rare for a successful spawn in a community tank.
Tiger barbs are voracious eaters the eggs would b lucky to even reach the substrate before being eaten up by them and in a breeder box it will most likely stress the pregnant TB... if your able to set up a 5-10 gallon and use marbles as the substrate it may give the eggs a chance to fall down into them to avoid gettin eaten... I seen a video where someone raised zebra danio fry that way and I’m sure a lot of other egg droppers would work that way as well... just from research no personal experience
Females carry the eggs but need the males to fertilize them. You could take out a pair and place them in a QT or an extra tank for a chance to breed. Otherwise, the community of barbs would probably just eat the eggs.