Ok first off remember to cycle your tank, if you don't know how to do a fish less cycle there's a great beginners resource center on this forum. Please, don't make the mistake soooooo many people do and get fish like tiger barbs which aren't compatible with many other fish.....read different forums, ask for ideas, etc. About fish until you're POSITIVE about which fish you want. Although tiger barbs are awesome, you could be stuck with them how ever many years they live, and not be able to house the fish you want...by all means though, go for tiger barbs, just make sure that's what you really want. I guess you could return your fish, but it's kind of a heartless thing to do if you don't know who the fish are going to, and what type of conditions they'll be going to.
To start, I would personally look at some fish that are somewhat more compatible than tiger barbs.
For example, something like a school of corycats is a great idea.
Or, another peaceful bottom feeder would be kuhli loaches, which would be perfect for your tank size.
Apistogrammas (a pair, semi agressive)
Bolivian ram (again semi agressive, stay away from German blue rams)
Cardinal tetras, you could have a nice school of about 10-12 in a 30 and leave room for much more
Rummy nose tetras (same as cardinals)
Most types of gouramis are peaceful/semi agressive
If you're in to the really colorful fish have a look at peacock gudgeons, or my favorite scarlet badis. I'm not sure if you could really call them a "schooling" fish, but they do need others of their own species and 5-6 would be great for a 30.
If you want a "2 species" tank you could fit 6 dwarf puffers and maybe 6-8 otocinclus.
Shrimp tank with small peaceful fish like cardinal tetras and celestial pearl danios
Just a few ideas
