Guppies and dwarf gouramis are both hardy, popular aquarium fish. They are both sold as community fish, meaning fish that get along with most other pets. They have similar aquarium and feeding requirements, making them a good pairing for your aquarium.
The guppy is among the world's most popular aquarium fish. They have much to recommend them for your aquarium. They are small, peaceful and extremely colorful. Additionally, they breed readily in captivity, so readily that fishkeepers often make the joke that the trick to breeding them is to put them in water. You also have a wide number of colorful varieties to choose from, and even various fin shapes. They are schooling fish and do their best in groups of at least three, with a ratio of two females per male.
The dwarf gourami has a lot in common with the guppy. They are small, colorful, and peaceful. Also, they prefer water without a lot of current. Unlike the guppy, the dwarf gourami hails from southeast Asia, in rice paddies and other stagnant water. Several color morphs are available. They do their best singly or in male-female pairs.
Both guppies and dwarf gouramis have very similar requirements, so you can easily accommodate both in the same fish tank. Both are tropical fish and will be comfy at 74 to 82 degrees Fahrenheit. Both fish prefer some cover from aquarium plants, but need open swimming areas as well. While guppies can be kept in a tank as small as 10 gallons, gouramis prefer a tank of at least 20 gallons (your guppies won't mind the extra space). However, if you want to get serious about breeding either species, you should probably keep them alone.
Both guppies and gouramis have very similar requirements in roommates. Anything they live with has to be small, unaggressiveness and not inclined to eat them. Any fish sold as a "community fish" will probably get along well with your guppies and gouramis.