At least four dwarf gouramis should be kept together. Dwarf gouramis are social creatures, and they feel more secure living in groups – the bigger the group, the better. With that said, if you have limited space, you can keep them in pairs.
Be careful not to overcrowd the tank, as it might stress the dwarf gouramis out. In general, one inch of fish requires at least a gallon of water to live comfortably. Keep in mind that dwarf gouramis can grow to be 3.5 inches long when mature. So, you can keep up to eight dwarf gouramis in a 55-gallon tank.