Assuming you have a dwarf gourami, you could add a couple/few more inches of fish, but it would be pushing it. If you have a normal gourami, you're probably maxed out (they can get big and sometimes mean). I expect you'll have problems with the tiger barbs. They can be very aggresive when not kept correctly. When in small schools they often focus this aggresion on other fish. In large schools they develop a firm dominance heirachy and usually keep to themselves. Seven is a little on the low side. Barbs are tricky. I've heard stories of new additions to established barb schools setting off a responce from the dominant male that ended in him killing not just a fair number of barbs, but also several other "inocent bystanders" as well. My advice is to keep tiger barbs in a speices set up (your catfish should be ok). Trade in the gourami for eight more barbs or trade in the barbs for a tetra species. Good luck