Profile of the Blue Gourami Fish

Cosby Hybrid

Blue gouramis are among the most durable aquarium fish available. They have only two spots—one in the middle of the body and the other near the caudal pentacle—and are a color variant of the three-spot gourami (beginning of the tail). What is the third position? It's the pupil! Their hues, which are usually silvery blue, alter dramatically depending on their emotions. They turn a significantly darker blue color during spawning. The opaline or cosby hybrid variety is unusual since it lacks spots and has deeper blue marbling.

Species Overview

Scientific Name: Trichogaster trichopterus

Common Names: Blue gourami, gold gourami, opaline gourami, cosby gourami, giant gourami, siamese gourami

Adult Size: 5 inches

Life Expectancy: 5 years


Family Osphronemidae
Origin Southeast Asia
Social Moderately aggressive
Tank Level All levels
Minimum Tank Size 20 gallons
Diet Omnivores
Breeding Bubble nest
Care Easy
pH 6 to 8
Hardness 5 to 35 dGH
Temperature 74 to 82 degrees F (23 to 28 degrees C)

Origin and Distribution

This widely distributed species may be found in nature across Southeast Asia. It may be found in southern China, Vietnam, Laos, Cambodia, Thailand, Myanmar, Malaysia, Sumatra, Java, and Kalimantan, as well as the Mekong River basin. Sulawesi, the Philippines, Taiwan, Papua New Guinea, and the islands of Reunion, Seychelles, Namibia, the Dominican Republic, Puerto Rico, and Colombia have all been imported outside of its natural range. The blue gourami may be found in shallow lowland marshes, swamps, and peatlands, as well as streams, canals, and flooded woodlands during flood season.

Colors and Markings

The blue gourami is a natural color variant of the brown or lavender gourami. It is generally whitish-blue in hue. It has two spots on its body, one in the center and the other near the base of its tail. If these patches begin to diminish, your fish is likely suffering from metabolic stress due to overpopulation or poor water conditions.

The species has a long, flattened body with big, rounded fins and a that allows it to directly breathe air. Males may grow to be five inches long, while females are somewhat bigger. Trichopterus is derived from the Greek terms trichiasis (hairy) and pteron (wing), and refers to their long, hair-like pelvic fins, which contain touch-sensitive cells.


Blue gouramis are territorial and may come into conflict with other species. Dwarf gouramis, guppies, goldfish, angelfish, and bettas should all be avoided. Tetras, loaches, danios, mollies, platies, barbs, and scavenger catfish are all better possibilities. To avoid aggressive behavior, use species that are comparable in size to blue gouramis.

Blue Gourami Habitat and Care

The blue gourami is one of the most resilient members of the gourami family. Their native habitat includes ditches, canals, ponds, marshes, rivers, and lakes, and they prefer heavily vegetated waterways of any kind.

Blue gouramis tolerate a wide range of temperatures and are not demanding in terms of water conditions. However, they prefer soft, slightly acidic water during the breeding season.

Tanks for young blue gouramis should be no more than 15 to 20 gallons, but as they grow older, they will require 35 gallons. Though they have a labyrinth organ and can breathe air if necessary, it is critical to maintain the tank well-filtered; air stones can also help with oxygenation. You could wish to use a darker substrate just because it contrasts nicely with the blue gourami's hues.

Blue Gourami Diet and Feeding

Blue gouramis are extremely easy to feed since they will eat almost any meal, including flake, freeze-dried, and live diets. They eat hydra voraciously and are appreciated for their capacity to rid the home aquarium of this problem.

Gender Differences 

Sexes are distinguished chiefly by the form of the dorsal fin, which is long and pointed in males and shorter and rounded in females. Females who are ready to spawn will have a noticeable enlargement, but the male will have a much thinner girth. During mating season, both sexes have a significantly darker blue tint.

Because the male might be hostile during spawning, the aquarium environment should include plenty of hiding spots for the female. Females may be injured if this is not done.

Breeding the Blue Gourami

Spawning begins with the male constructing a bubble nest, which happens early in the day. The male will attempt to attract the female under the nest by swimming back and forth, flaring his fins, and elevating his tail when a good nest has been made. The female indicates her ready by biting his back; he reacts by stroking his back against her belly several times before engulfing her in a spawning hug.

The male wraps his body firmly around the female during spawning, turning her on her side or back so the eggs may rise to the surface unhindered. This intimate hug is also beneficial since it puts the reproductive parts as near as possible together. Because sperm cells only last a few minutes in water, the order in which they are released and their closeness to the eggs are crucial.

The couple may be seen shivering just before the sperm is expelled, indicating that spawning is nearly complete. After then, the eggs are released and fertilized by the time they reach the bubble nest. Over the course of many hours, the duo may repeat the act multiple times. The number of eggs produced might easily exceed the thousands.

Once spawning is accomplished, the female's role is over; remove her to avoid a male attack. The male will care for the eggs from now until they hatch, meticulously rearranging them and returning any errant eggs to the nest. During mating, male gouramis may spit streams of water, which is an unusual phenomena. The objective of this action is thought to be to maintain the eggs positioned within the bubble nest.

In around 30 hours, the eggs will hatch. Feed infusoria and nauplii to the fry. As the fry grow, do regular water changes, especially during the third week, when the labyrinth organ develops.

More Pet Fish Species and Further Research

If blue gouramis appeal to you, and you are interested in some compatible fish for your aquarium, read up on:

Checkout additional fish species profiles for more information on other  fish.


"Degani, Gad, Bar Ziv, Michael. Male Blue Gourami (Trichogaster trichopterus) Nest-Building Behavior Is Affected by Other Males and Females. Open Journal of Animal Sciences, 6,3, 2016, doi:10.4236/ojas.2016.63025" ;