Sexing Gouramis isn't done the same way as determining the gender of livebearing fish. If you want to breed them, discovering which are male and female is important. This guide will help you determine the gender of Gouramis and how they breed.
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 fin that comes to a point. Keep in mind that young fish are not as easy to differentiate as full grown adults. In younger fish, the fins are not fully developed and they have not attained their adult size.
There are many species of Gouramis and some can be a challenge to breed, while others, like the Blue Gourami, readily breed in aquariums. You will need to do two things to encourage breeding. First is to prepare a suitable tank and the other is preparing 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 would, because most tanks are not going to satisfy the male enough to make him build a nest of air bubbles at the surface to entice the female to lay eggs. The male is the dominant mate but the female is the one who makes the choice in regards to breeding.
To prepare Gouramis for breeding, feed them a varied diet that includes flake food, algae wafers or spirulina flakes, along with freeze-dried bloodworms, tubifex, and brine shrimp. You can also feed them live foods and some fresh veggies like chopped lettuce or cucumber for a few days. 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. She is very fat and full of 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 next 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. Gouramis are labyrinth fish so they can live in poorly oxygenated water because they will go to the surface to breathe air.
It is very important to have loose branches and leaves of aquatic plants floating on the surface of the water as these are used by the male in building his bubble nest.
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 while defending the eggs in the nest and later the fry (baby fish). Once the eggs start hatching, you should also remove the male because if something bothers him, he could eat them all. In the wild, once the fry hatch out his job is over; the fry scatter to eat infusoria and he is off to find another female to mate with. When breeding gouramis it is important to have a small food available to feed the fry once they leave the bubble nest; baby brine shrimp (frozen is fine), microworms or finely crushed flake food will work.