The Barzans were a humanoid species native to the planet Barzan II. In appearance they had light-copper to tan skin, with some facial ridges and a hairline set far back from the forehead. When leaving their homeworld, they had to wear a breathing device which provided them with the gases that are found in the toxic atmosphere of Barzan II.
The Barzans were a resource-poor species and technologically only moderately advanced. When the Barzan wormhole was discovered in 2366, the lack of other resources was a major factor in the Barzans' decision to sell rights to the wormhole to the highest bidder. (TNG: "The Price")