When a female gourami fish is pregnant, her belly is swollen at all times, according to Fish Spawn. The male builds a bubble nest before the bulge is visible. A bubble nest looks like a cluster of many tiny bubbles that float on the surface of the water.
During the first stage of gourami breeding, the male and female swim alongside each other for a few days. If the tank's temperature is between 78 and 80 degrees Fahrenheit and there is an adequate food supply, spawning successfully initiates. Some species of female gourami have been known to eat their eggs, so Fish Spawn recommends temporarily removing the female from the tank after she lays her eggs.