Well, to answer your question, just one (male I assume) would be fine.
HOWEVER, whether you should get one or not in the first place depends on various things.
Firstly, is your tank cycled? Dwarf gouramies are not a beginner's fish. They aren't as hardy as they ocne were and can contract diseases very easily and often die from them. Stress from bad water quality has a very negative affect on them.
Next, what size tank? Dwarf gouramies only get to 2" so, actualy, they do ok in quite a small tank. However, because of their fragile nature, a crowded tank or one that is much too small can have serious negative effects on them. Also, the stress from the instability of smaller tanks can have serious reprocutions if not carefuly controlled.
And that brings me to what other fish will be with it and how many of each? Like I mentioned before, dwarf gouramies can be easily stressed. They are also prone to having their ventral 'feelers' nipped so fish likely to nip like tiger barbs are not good tank-mates. They also don't usualy appreciate being with other, especialy mroe aggressive, gouramies and preffer a planted tank with lots of floating plants for cover and to establish an undisputed territory. However, do keep in mind that they are 'labyrinth fish' so they breath directly from the air, somewhat ike we do. As such, you have to make sure they have access to atmospheric air at all times - or they will literally suphocate.
I obviously don't know how much of this you new already but, hopefuly, I have helped you a little. I did, at least, answer your original question.
Anyway, welcome to the forum!
