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The Dwarf Gourami

The Dwarf Gourami (Polyacanthus lalius)

By Mike Hellweg

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The dwarf gourami has developed a labyrinth organ to survive the poor waters they live in
The peaceful, beautiful dwarf gourami has been in the hobby for more than 75 years—and this species will spawn without too much intervention from aquarists. Photo credit: Gary Lange

The dwarf gourami can be found swimming in the canals, irrigation and drainage ditches, rice paddies and other slow-flowing shallow bodies of water of India. This water is warm, muddy, choked with vegetation and often devoid of oxygen.

To survive in this harsh environment, the dwarf gourami has evolved with an auxiliary breathing apparatus known as the labyrinth organ. This organ functions similarly to a lung. The fish takes in gulps of air from the surface and passes the air into the labyrinth. Here, the myriad of capillaries extracts oxygen from the air and gets rid of carbon dioxide. It has become so dependant upon this ability to extract atmospheric oxygen from gulps of air that it can actually drown if unable to reach the surface.

Until recently, the dwarf gourami was known as Colisa lalia, but as often happens with scientific names, it was renamed to Polyacanthus lalius. Whatever the scientists want to call it, we hobbyists have given it a place in our aquariums for more than 75 years. They are beautiful, undemanding, peaceful, and they can be encouraged to spawn without too much work on the part of the aquarist. In the past decade, several color variants have become extremely popular: These are various shades of metallic green, light blue, orange, red, yellow and even cream. They have become so popular that it has become difficult to find wild-type fish--but whatever the color, they are still all the same fish.

Wild dwarf gourami males are a sight to see. They are stocky, heavy-bodied fish. A really big male will top out at about 2 ½ inches. Big adult females are about half an inch shorter; but what really makes the males stand out is the series of at least 12 rust-colored bands starting at the head and ending at the tail. Between these rust bands are a series of bright metallic blue-green bands that in the right light can make him look like he’s glowing. This blue-green color extends into the dorsal, caudal and anal fins. Females also have a series of bars along their flanks, only they are silver and pale gray. The female coloration is so pale compared to the males that often only males are shipped because dealers complain that they can’t sell the plain females. As you can imagine, this can often makes finding a pair a real challenge.

In a dealer’s bare aquariums, it’s easy to overlook dwarf gouramis. They’ll be pale because they’ll be frightened (even the normally colorful males can be a washed-out silver and dull red in this state). Because they may be uncomfortable in bare shop aquariums, they will be trying to hide wherever they can. Bring them home and give them an aquarium full of hiding places and with a lot of aquatic plants, and they’ll be out in the open, showing off their coloration all the time; even wild-type females will become quite a bit more colorful.

You may notice that these gouramis spend a lot of time exploring their aquarium and touching everything (including other fish) with their threadlike pelvic fins. These fins are very sensitive and help the gouramis find food, mates and even the way through the muddy waters of their home in the wild. In our clean, clear aquariums, the gouramis still appear to use this interesting behavior continuously. These fish should not share their aquariums with likely fin-nippers. Smaller rasboras, danios, tetras and small barbs (i.e., cherry barbs and checkerboard barbs) are ideal.

A 15- or 20-gallon aquarium is perfect for a group of dwarf gouramis. Keep more males than females; one male per aquarium would be ideal with two or three females. As the fish mature and females begin to fill with eggs, you might want to think about getting them to spawn. A ripe female dwarf gourami will look like she has swallowed a marble. She’ll also show a small whitish bump near the anal pore, just in front of the anal fin. This is the egg tube, and it’s a sign she’s ready to spawn.

It’s a good idea to move the dwarves to a separate aquarium for spawning. For a single pair, use a 10-gallon aquarium filled 6 inches deep with water. They’ve been bred in captivity for so long that water parameters have become unimportant, as long as extremes are avoided. Soft water with a neutral pH is best but not entirely necessary anymore; but there are a few things that every breeding aquarium will need.

The breeding aquarium must have live aquatic plants. The male and female work together to build a bubblenest out of saliva-covered bubbles, and they weave plant matter into the nest. Without the plants, they often won’t even begin construction of the nest. Floating plants like Riccia, Hornwort (Ceratophyllum spp.), and stem plants such as Myriophyllum or Cabomba are most often used, but others will do in a pinch. The nest will often cover a quarter of the aquarium’s surface, and extend up to a 1½ inches above the surface. This is a sturdy nest that will last for quite a while. Some nests will last for nearly a month after the fry are gone.

Also, heat is a necessity. The aquarium should have a heater set at 82 to 84 degrees Fahrenheit. A filter is not necessary, nor is aeration. In fact, aeration would make it hard for the fish to construct the nest. The final things that are needed are a couple of hiding places for the female to be able to escape the male’s attentions after spawning is done. He can become a bit aggressive, and males have been known to kill females that have not been removed from the aquarium after spawning.

Leave the male with the nest. He will spend the next few days caring for the nest and the newly hatched fry. He does not eat during this period. Dwarf gourami eggs hatch out very quickly, often within just 12 hours of being laid. The larvae are very tiny and spend several days just hanging in the nest while they complete their initial development. About five or six days after hatching, they make their first attempts at swimming. The male will dutifully chase the fry down, gently catch them in his mouth and spit them back into the nest. As more fry begin to swim, this becomes a full-time job for the male. At some point after a couple more days, he begins to eat the fry instead of spitting them back into the nest. Before this happens, remove the male. It’s probably best moving the male sometime between the fifth and the seventh day after spawning.

Dwarf gourami fry are tiny, even after free-swimming. They require tiny fish foods. One of the best fish foods for them is what is known as “green water.” This is basically water filled with single-celled algae and small single-celled animals known as protozoa. They will eat the microscopic life for the first several days after becoming free-swimming and should be fed several times a day. When you look at them, you should see bulging bellies. If not, you need to add more fish food. The majority of fry that die during this stage of life will perish due to starvation. You can also feed them commercial fry foods, but if you do, make sure you add some snails to clean up the uneaten fish food.

At about day 10 after removing the male, you can start adding newly hatched brine shrimp and vinegar eels (an easily cultured tiny aquatic worm) along with the green water. Once all the fry have bright orange bellies after feeding, you can discontinue the green water, as they are now all eating the brine shrimp. You still need to feed heavily and watch for disparity of growth. For some unknown reason, a few anabantoid fry, including those of dwarf gouramis, will grow more rapidly than their siblings. At a certain point, they will begin to consume their smaller brothers and sisters. Needless to say, they should be separated before this stage occurs.

Once they have reached about a half inch or larger, you can start adding finely crushed flake to their diet. Mix it with the feedings of brine shrimp until they are all eating it. At this point, you can also start doing water changes and add a gently bubbling, mature sponge filter to the aquarium. You should have quite a few young fish on your hands, as a good spawn can number into the hundreds. Consider separating them into several larger aquariums (known as “grow-out aquariums”) where they can continue to grow without being too crowded; once they reach about one-half inch, you can keep 30 per 10-gallon aquarium, cutting the number of fish in half as they start to reach 1 inch.

At this point, you should have no trouble finding homes for the young, as there are always hobbyists looking for young aquarium-raised dwarf gouramis, especially since females can be so hard to find. Congratulations! You’ve had another successful adventure in fish breeding!

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