Hi Sasha
Since you live in the US, it is likely that most of the dwarf gouramis will be male. There are exceptions like Sunset Dwarfs and the regular old fashioned, red and blue striped Dwarf Gourami.
For the standard varieties, the easiest way is to look at them from the top. The males taper smoothly back from head to tail, while the females are rounded in front and then taper back. Once you look at them this way the difference will be clear.
The males also have longer and more pointed dorsal and anal fins. Those of the female tend to be shorter and rounder.
Look at the examples on this thread:
http
/fish.orbust.net/forums/index.php?sh...=0&#entry184066
The first picture is a pearl gourami female and the third is a male. There is also another picture (by rain) of a more mature male. If you pay attention to the fins you will notice the difference.
I hope this was helpful to you.
How do you tell male Gouramis from females? I'm not quite sure how to tell them apart and need a little advice. I examined the Gourmais at the pet store, but they both look the same. I'm planning to get a few Gouramis for my 46 gallon tank and I want to be able to know which are females and which are males. . . or I'll end up with two males fighting or a breeding pair! Any help advice would be appreciated! 
