gourami – Fish Laboratory Aquatics

Moonlight gourami are named after their beautiful silvery appearance. They have long flowing ventral fins that are used as feelers to sense their surroundings. As labyrinth fish, they have a special lung-like organ that allows them to breathe water directly from the surface. They often come up to the surface to gulp air, rather than using their gills. In the wild, this ability helps the fish survive in low oxygen environments such as ponds. The moonlight gourami originates in the tropical areas of Indonesia, Malaysia, Vietnam, and other parts of Southeast Asia. They are often found in slow moving waters such as ponds, swamps, and lakes. They spend most of their time near areas of heavy vegetation. Scientific NameTrichogaster microlepisCommon Name(s)Moonlight Gourami, Moonbeam GouramiOriginSoutheast AsiaTemperature Range77-86°FWater Parameter(s)pH 6-7.5, 2-25 dGHAdult Size5-6”DietOmnivorous Moonlight Gourami Moonlight Gourami Facts: Moonlight gourami can breathe air directly from the surface, thanks to their labyrinth organ.Long ventral fins are used to sense their surroundings.They are one of the larger species of gourami, but rather timid. Moonlight Gourami Care Moonlight gouramis are hardy fish, and they are not difficult to take care of. Their labyrinth organ enables them to breathe in low oxygen environments that other fish would not be able to survive in. However, regular water changes are important because they consume lots of food, and the toxins in the water can build up quickly. The toxins in the water will result in tissue damage, as it would with any other fish. Tank Setup Since moonlight gourami are timid fish, you should provide lots of hiding places. An aquarium setup with lots of plants would be ideal. Keep in mind that moonlight gouramis do eat plants. They will chew on fine-leaved plants regularly. Sturdy plants such as Java fern and anubias should be fine. Tank Size The minimum tank size for a moonlight gourami is 20 gallons. However, if you intend to keep multiple fish or you have lots of plants, the recommended tank size is 30 gallons. This is important because they are one of the larger species of gourami and they can grow to a significant size. An adult moonlight gourami can reach up to 6 inches. Feeding Feeding moonlight gouramis is not difficult. They will eat flake, frozen, and live food. Since they are omnivorous, they should be fed a varied diet. In the wild, moonlight gouramis eat insects and other invertebrates, as well as small amounts of plant matter. Moonlight gouramis are timid, and other fish can outcompete them for food. These fish will forego food instead of picking a fight. In a community tank with other aggressive or larger fish, make sure they are getting their share of the food. Tank mates Tank mates for moonlight gouramis should be non-aggressive fish. Other labyrinth fish, corydoras, and angelfish may be suitable tank mates. Moonlight gouramis are not aggressive fish. However, males are territorial and can become aggressive towards each other. Therefore, moonlight gouramis should be housed with a single male per tank. However, multiple females can be housed in a tank without an issue. If there are multiple males in a tank, the tank should be large enough to allow each male to establish their own territory. Lifespan The average lifespan of a moonlight gourami is 4 years. However, in a well-kept aquarium, some reach 6 years of age. Sexing Sexing a moonlight gourami can be difficult, but it is possible. Males are more slender than females. They also have longer and more pointed dorsal and anal fins. The coloration is stronger in males. The males’ pelvic fin and ventral fins are orange, while the females’ are more pale or colorless. Breeding In order to breed moonlight gouramis, slightly softer water and higher temperature is required. The temperature should be raised to approximately 80°F. Feeding live food will help condition the breeding pair. Like most gourami, moonlight gouramis build bubble nests for their young, so having floating vegetation is essential if trying to breed this species. Heavy vegetation will help the breeding pair feel secure as well. Under the right circumstances, they are fairly easy to breed. Once the male creates the bubble nest, he will court the female with a dance. He will then turn her onto her back so she can release her eggs. The female can lay up to 2000 eggs. He will then fertilize the eggs and place them inside the bubble nest. The eggs will hatch after a 2-3 day incubation period. The male will protect the fry until they become free swimming, which will take 5-7 days. The male can become slightly aggressive towards the female during this period, so having lots of plants will help the female hide if necessary. The female can be removed from the breeding tank as well, especially if the male is particularly aggressive. Once the fry is free-swimming, both the male and female should be removed from the breeding tank. The fry are very tiny, so they will require small foods such as infusoria and green water. After a few days, they can be moved to slightly larger food such as microworms and baby brine shrimp. Rather than feeding the fry a large portion of food once a day, giving them small amounts of food throughout the day is better. In the beginning, they should be fed at least 3 times a day.