Sexing Gouramis isn't the same as determining the gender of livebearing fish. But if you want to breed them, discovering which are male and female is important. Here are ways to determine the sex of Gouramis.
Male and Female Gouramis
Male Gouramis are usually a bit smaller than the females and are slimmer in overall girth. Females have a rounded belly compared to the males. However, the dorsal (top) fin is the most distinctive difference that can be seen between males and females. The dorsal fin of the female is short and rounded, while the male has a longer dorsal that comes to a point.
Keep in mind that young fish are not as easy to differentiate, as the fins are not fully developed and they have not attained their adult size.
There are many types of Gourami, and some can be a challenge to breed. You will need to do two things first. One is preparing a suitable tank and the other is prepared the fish for breeding.
Normally you just can’t put a pair of Blue Gourami into a tank and expect them to pair up and breed like livebearers because most tanks are not going to satisfy the male. The male is the dominant mate but the female is the one who makes the choice on breeding.
At breeding time, the male becomes vibrant and much darker than the female. The female Blue Gourami in prime breeding condition will look she ate a golf ball -- very fat with eggs. You will know it when you see this; there is no question she is ready.
If the male doesn’t like the surroundings he will not build a bubble nest. If there is no nest there will be no place for the female to deposit her eggs. So, the first thing that you need to do is get a tank ready that will suit the male.
The Best Tank Environment for Breeding Gourami
The tank itself should ideally be around 20-gallons, long, with older water and floating plants. The tank temperature should be somewhere between 74 F to 79 F and the pH should be somewhat neutral to slightly acidic. Gouramis prefer relatively soft water, and a well-planted tank is always a plus.
The tank shouldn’t have an air stone or filter because the male likes calm water to build his nest in. If the water has too much turbulence he will not even try to build a nest and they are labyrinth fish so they can live in poorly oxygenated water because they will go to the surface to breathe.
It is very important to have loose branches and leaves of aquatic plants floating on the surface of the water; this is how the male structures his bubble nest. You can prepare the fish by feeding the pair live foods and some fresh veggies like lettuce or cucumber for a few days.
How Gouramis Breed
The basic routine for mating is the male will prepare a bubble nest for the chosen female and he will then chase her around, sometimes violently, until she submits and inspects the nest. If she is impressed with his work and accepts his home for her eggs, she will present herself in a way that lets the male know she is willing to deposit her eggs there.
At this point, the male will then roughly embrace the female by wrapping himself around her to help her expel the eggs up into the nest. Any eggs that don’t get deposited into the bubble nest will be gathered by the male and blown in a bubble back into the nest. Once they have spawned you should remove the female and leave the male to care for the eggs.
If you do not remove the female, and she is not a good hider, the male may kill the female defending the eggs in the nest, and later the fry. Once the eggs start hatching you should remove the male also because if something bothers him he could eat them all. In nature, once the fry hatch out his job is over; they scatter to eat infusoria and he is off to find another female to mate with.