Trichogaster lalius (Dwarf Gourami), once a popular aquarium fish known for its sparkling color and resistance to poor water quality, has unfortunately lost its hardiness over the past decade due to extensive selective breeding, Asian disease, and poor maintenance in mass production.
As a result, Dwarf gourami is no longer recommended for beginners. In addition to being less hardy, they are also very timid and stress easily.
In this article, I will describe all that is known about Dwarf gourami and the problems associated with them.
Quick Notes about Dwarf Gourami
|Scientific Name||Trichogaster lalius (formerly called Colisa Lalius)|
|Tank size (minimum)||15 gallons (~60 liters)|
|Size||up to 2 – 3 inches (5 – 7 cm)|
|Optimal Temperature||68 – 79°F (20 – 26°C)|
|Optimal PH||6.5 – 7.5|
|Optimal GH||4 – 12|
|Dwellers||Top to mid-dwelling|
|Nitrate||Less than 60|
|Life span||up to 2 years|
|Color Form||Predominantly scarlet with slanted stripes (natural color)|
Etymology of Trichogaster Lalius
The genus name “Trichogaster” comes from two Greek words “Trichos + Gastēr ” meaning “Hair,” and “Belly.” This refers to the fish’s distinctive hair-like appendages on its belly.
The species name “Lalius” is derived from the Latin word “Lalus,” meaning “Small or dwarf” due to its relatively small size compared to other members of the Trichogaster genus.
Therefore, the full scientific name Trichogaster lalius can be translated as “the small, hair-bellied fish”.
Distribution of Dwarf Gourami
However, in recent years it has also become established through various means, such as intentional releases and accidental escapes in Australia, Columbia, and the United States.
Habitat of Dwarf Gourami
In their natural habitat, these fish are mostly found in stagnant freshwater water such as pools, ditches, ponds, wetlands, rice fields, irrigation channels, lakes, and marshes. However, sometimes they can also be found in slow-swimming streams and rivers.
Dwarf gourami prefer shallow areas or other quiet habitats where they can hide in leaf litter and dense aquatic vegetation.
Description of Dwarf Gourami
Dwarf gourami are a small fish species. According to some studies, they can grow up to 3 and ½ inches (8.8 cm) in length. However, in aquariums, the average size of adult fish is about 2 – 3 inches (5 – 7 cm) in total length.
Distinguishing characteristics of Dwarf Gourami:
- Body shape. This species has an egg-shaped body that is strongly compressed from the lateral side.
- Mouth. It is small and directed upwards. The lip is normal.
- Fins. The dorsal and anal fins are soft, spiny, and slightly concavity over nape. The tail fin is round to truncate. The pelvic fins are shaped as long thread-like feeders which can be moved in all directions.
- Color. The body is predominantly scarlet. There are slanted pale blue stripes (descending downwards and backward from the back to the abdomen) that shimmer with a translucent blue hue. There can also be scarlet live spots and bars on fins and with a red margin in the anal fin. The lateral line is incomplete.
|Because of selective breeding, nowadays, there are many color morphs of this species, including:
Note: These fish have an accessory respiratory organ called a “labyrinth organ” located next to gill cavities. This delicate tissue has a high concentration of blood vessels and functions like terrestrial lungs
Interesting fact: Dwarf gourami has the ability to breathe air from the water’s surface thanks to a unique organ called the labyrinth. This specialized structure is located beside the gill cavities and consists of folded membranes supported by a bony framework. These membranes are delicate but densely packed with blood vessels, functioning much like lungs found in terrestrial creatures. It allows them to survive in environments where oxygen levels in the water are low.
For a detailed description of Trichogaster lalius, you can refer to this scientific paper.
Lifespan of Dwarf Gourami
Currently, there is no data available on the maximum lifespan of Dwarf gourami in the wild.
Many guides on this fish species suggest they can live up to 5 years. Unfortunately, this is not typically the case. In the vast majority of instances, they will live a maximum of 2 years, even if appropriately cared for.
It’s important to consider that several factors strongly influence their lifespan, for instance:
- Temperature. High temperatures (more than 77°F or 25°C) accelerate their metabolism, reducing their lifespan by nearly half.
- Frequent mating. Continuous breeding also leads to physical exhaustion and shortens their life.
- Genetics. Stress and weak genetics, often associated with fish breeders’ selective breeding, have also significantly impacted their longevity.
Additionally, it’s important to note that when we purchase these fish from stores, they are typically around 4 to 6 months old. This age should also be considered when estimating their overall lifespan.
Typical Behavior of Dwarf Gourami
Most articles describe Dwarf gouramis as peaceful and gentle fish that make them a popular choice for community aquariums. They are very shy and hide away from loud sounds and even slight disturbances.
Even though it is generally true for large and heavily planted tanks, there are also lots of BUTS…
- Despite their small size, males of Dwarf gouramis become very territorial during breeding. They will fight, chase, and nip all other fish in the tank.
- Males together often lead to fights, and one may end up dead if there is not enough space for each one to claim its own territory.
- Mixing males and females is also not without risks. Males can become excessively aggressive when they are attempting to breed, which may result in causing harm or even death to the females.
Despite the fact that this species tends to feel more confident in a group (3-4), it can also lead to intraspecies conflicts, especially during the breeding season, as mentioned earlier.
Therefore, it is advisable to keep just one fish, especially if you have a small aquarium with limited vegetation where other fish can hide.
|Tip: Once alone, that is when their peaceful nature truly emerges.|
They are relatively active swimmers. However, they do not swim in the tank like crazy.
Once they find something new in the tank, it is interesting to see them examining it with their feelers.
Dwarf gouramis are capable of jumping out of the tank, although it is not their common behavior. In most cases, it happens if they are stressed or if the water quality is poor.
Placement in Tank:
Dwarf gouramis prefer the middle and top layers of the tank.
- Social: Yes
- Activity: Average
- Placement: Middle – top dwellers
- Peaceful: Yes (conditionally)
- Nippers: Yes
- Jumpers: Yes (rarely)
Feeding Dwarf Gourami
Trichogaster lalius is considered omnivorous with a predominantly carnivorous appetite. They are not picky eaters and will happily consume animal and plant matter (algae).
In their natural habitat, Dwarf gouramis feed on a wide variety of food including detritus, debris, micro-zooplanktons, worms, insects, and small crustaceans.
In aquariums, they enjoy feeding on a wide variety of natural live food including:
- brine shrimp (artemia salina),
- tubifex worms,
- grindal worms,
- cyclops, etc
For the best for their growth and coloration, feeds should contain protein at a level of about 30-40%, 4-9% lipids, and 30-40 % carbohydrates in their diets.
Note: According to the study, 35% protein in the diet resulted in the greatest increase in weight and length. In general, gouramis require 30-45% protein, 4-9% lipids, and 30-40 % carbohydrates in their diets.
This fish can reared in artificial diets – dry and freeze-dried foods such as flakes, pellets, and crisps as long as it is adapted to their mouth size.
Enhance Dwarf Gourami Coloration – Astaxanthin
Bright and intense coloration is very important in ornamental fish. Unfortunately, they cannot synthesize carotenoids in their body and must obtain them via food.
Astaxanthin and canthaxanthin are common carotenoid supplements that significantly enhance the coloration, particularly their red and orange hues.
- Commercial products. Look for goldfish food that contains astaxanthin as an ingredient. This will improve their vibrant colors.
- Spirulina and Krill. Spirulina and krill are natural sources of astaxanthin. Feeding your Dwarf gouramis foods that contain these ingredients can help enhance their coloration over time.
How to feed Dwarf Gouramis
From a scientific perspective, we need to provide them daily with food roughly equivalent to 3-5% of their body weight.
Of course, in most cases, only a few people will bother with such calculations, and therefore the «5-minute rule» remains the best option for the average aquarium enthusiast.
The fish should consume all the food within 5 minutes, and if there is anything left, it’s a sign of overfeeding.
Dwarf gouramis are not very fast swimmers. So, if you have other fast-swimming fish in the tank, food should be dropped in a more spread-out area. It will give them more chances to get their share.
- Diet Type: Omnivore
- Food Preference: Meat
- Feeding Frequency: Daily
Are Dwarf Gouramis Plants Safe?
Although Dwarf gouramis are generally compatible with aquarium plants (they do not consume healthy plants) but with some considerations.
The main problem is that males are enthusiastic nest builders.
During this construction phase, they may inadvertently damage delicate plants or uproot small ground-covering plants to incorporate plant fragments into their nests.
Keeping and Caring for Dwarf Gouramis
Wild Trichogaster species are hardy and highly adaptive. Unfortunately, the same cannot be said for selectively bred Dwarf Gouramis.
In my opinion, when it comes to these selectively bred variants, it’s a bit of a gamble, and sometimes the odds don’t favor you. Unless you provide them with the right conditions, there can be issues, which are not uncommon.
Additionally, I would recommend buying juvenile Gouramis. This is because younger Gouramis are more likely to adapt to their new environment.
DO NOT introduce them during or immediately after completing the aquarium cycling process. Wait for at least a couple of weeks until the balance is completely established.
This small fish is ideally suited to small to medium-sized tanks.
If you are keeping or planning to keep just one Dwarf Gourami, a 10-gallon (40-liter) tank will be enough. This provides ample space for it to swim and explore.
For a small group of 2-3 Dwarf Gouramis, a tank of around 20-30 gallons (80-120 liters) is a good starting point (if you have 2 females and 1 male). However, the larger the tank, the better, as it allows for more swimming space and can help reduce territorial disputes.
If you have a choice, it’s best to opt for a larger tank because:
- Always keep in mind that they are territorial and can be quite aggressive with each other if there is not enough space for each one to claim its own territory.
- Maintaining water balance and parameters is easier in larger aquariums because they provide a larger volume of water.
- This allows for more stable water conditions and dilutes any potential fluctuations in water chemistry.
Additionally, long tanks are better than tall tanks of the same size.
|Important: Lots of hiding spots and ample vegetation can help reduce stress and aggression in the aquarium. Unfortunately, it is hard to do in small tanks.|
Temperature: This species needs water temperatures ranging between 68 to 79°F (20°C to 26°C). Trichogaster lalius can tolerate even slightly cooler temperatures if acclimated very slowly.
Results of the 90-day experiment, which involved various temperature regimes (68°F (20°C), 77°F (25°C), 86°F (30°C) and 95°F (35°C)), showed that:
- optimal temperature for growth rate and weight gain was 77°F (25°C).
- survival rates were higher at both 68°F (20°C) and 77°F (25°C). There was only 1% mortality, whereas at 82°F (28°C) was already 10%. The lethal temperature at which 50% of the population died was 102°F (39°C).
|Water temperature outside the optimal range will have significant effects on the growth and formation of Dwarf gouramis|
pH: According to the study, the best growth, survival, and culture conditions were observed in the control group with a pH of 7.0. Lethal concentration (at which 50% of the population dies) was pH 5.71 and 8.22.
When the water’s pH falls below 6.5 pH or rises above 7.3 pH, Dwarf Gouramis are at risk of developing skin issues and infections that can be difficult to treat. Additionally, they become more susceptible to oodiniosis, also known as Velvet disease.
Therefore, in aquariums, the recommended range is 6.5 – 7.5 pH.
Hardness: The tank should preferably have medium to slightly hard water hardness. Thus, anything in the 4 – 12 GH range is acceptable.
Salinity: Dwarf gouramis cannot tolerate salinity very well. For example, experiments showed that they can be safely exposed to water salinity levels up to 4 g/L without experiencing mortality. However, the concentration of 5.81 g/L corresponds to the maximum lethal salinity.
Subdued lighting will be the best choice for the Dwarf gouramis. However, in planted tanks, lighting should be adapted to the needs of plants.
According to the study, a 16-hour light duration exhibited the highest absolute, specific, and relative growth rates compared to 0L:24D and 12L:12D. This improvement is attributed to processes like photostimulation and increased feed intake, which enhance feed conversion efficiency.
In their natural habitat, these fish prefer stagnant waters. Therefore, it’s advisable not to create strong water currents in the aquarium, as it can be stressful for Dwarf gouramis.
Substrate doesn’t play a significant role for them. You could even skip it.
However, in a bare-bottom tank, the light reflecting off the aquarium’s bottom can confuse the fish and make them a bit nervous.
Therefore, it is still better to go with at least a thin layer of substrate.
As long as you have got the filter that works great with the size of the tank you have got you will be fine.
Make sure that your Dwarf gouramis have lots of hiding places. They are pretty skittish.
Provide them with lots of floating plants, since they like to take a rest there. Additionally, dense and tall plants, like Vallisneria, Ludwigia, Elodea, Anacharis, etc. will divide territory and can provide invaluable assistance to a female tired of the persistent advances of males.
Breeding Dwarf Gouramis
Dwarf gouramis are well known for their interesting reproductive behavior which includes bubble nesting and parental care. Under optimal conditions, this species can be easily bred even in a confined environment.
For example, in Singapore, they can bread all year round with newly hatched fry reaching sexual maturity in as little as four months. Whereas in northern India, it takes them 8 to 12 months to mature.
Only mature Dwarf gouramis exhibit secondary sexual dimorphism and can be distinguishable by several key features:
|Body size||Larger||Little smaller|
|Body-color||Brightly colored||Less colorful (silvery or dull silvery)|
|Color pattern||The obliquely disposed of lateral bands on the body are peacock blue.||These bands are dull steel gray|
|Upper lip||More pronounced||Not much pronounced|
|Fin morphology||The dorsal and pelvic fins are more pointed at the posterior end.
Also, the dorsal fin is longer and reaches back to the middle caudal peduncle.
|The dorsal and pelvic fins are rounded or curved.|
|Fin color||The pelvic fin is a single ray that becomes orange-red later: during breeding season dorsal and anal fins become peacock blue with an orange border.||The pelvic fin is yellowish-gray: during breeding season dorsal and anal fins become yellowish-gray.|
(during the breeding season)
|Slender belly.||Bulging abdomen.|
|Bubble nest||Build bubble nests||No|
|Temper||Territorial and more aggressive||Peaceful|
- In Dwarf gouramis, female pheromones can elicit male nest-building.
- Males initiate mating by building a bubble nest.
- The male courts the female swimming around her with flared fins to draw her to the nest. He also stimulates the female by touching her ventral side by its mouth.
- Once the female responds and shows interest, the male stops chasing and focuses on nest-building. The pair becomes ready for spawning when the nest formation is completed.
- The female starts laying eggs (around five dozen clear eggs) and the male quickly fertilizes releasing milts over them.
- After every mating, the male collects the eggs in his mouth for a few seconds and adds saliva to make them sticky.
- The male produces more air bubbles to encase the eggs in the nest and keep them afloat.
- Spawning sessions can continue for 2 to 4 hours. Dwarf gouramis mate several times at intervals of 30 seconds to one minute.
- After that, the male guards the eggs and the hatchlings, while not allowing the female or other fish near the nest.
- Male Dwarf gouramis construct a floating bubble nest, incorporating bits of plants, twigs, and other debris to hold it together.
- Depending on the temperature, the time taken to build a bubble nest varies:
- 24 hours 82°F (28°C)
- 32 hours 77°F (25°C)
- 72 hours 72°F (22°C)
- Most of the eggs float up into the bubble nest, and any strayed eggs are collected by the male.
In Dwarf gouramis, the absolute fecundity is ranged from 1000 to 1350. On average, females produce between 300 and 800 eggs.
The fertilization rate is around 60%.
The fertilized eggs are spherical in form. The diameter of eggs usually ranges from 0.6 to 0.7 mm. They are golden in color and optically transparent.
Eggs are lighter than water. Therefore, they go to the bubble nest on the surface, those that cannot go up are carried by the male to the nest.
The incubation period depends on the temperature. For example, it is around 24 hours at an average water temperature range of 73 – 79°F (23 – 26°C).
The embryonic development is divided into several stages such as:
If you want to know the details of each stage, check out this study. You can find a detailed description.
After hatching, the fry initially attach to the bubble nest for about 2 – 3 days, absorbing their yolk sacs. They are around 1.7-2.0 mm in length and have transparent body.
Once the yolk sac is fully absorbed, they become black, comma-shaped, and free-swimming.
The male should be removed to prevent him from eating the young.
If you want to know details of fry development, check out this study. You can find a detailed description.
After yolk sac absorption, fry immediately requires live food such as (rotifers, vinegar eels, microworms, or infusoria) for the next 2-3 weeks. Starting from the 3rd week, they can be fed with Artemia.
Live food is the best choice for fry. In one of the experiments, different types of food (food, egg yolk, and commercial pellets) were compared to understand their impact on growth and survival.
- Live food. Fry had the highest survival rate of 100%.
- Egg yolk. Fry had yolk had a survival rate of 66%.
- Commercial pellets. They had a survival rate of only 46%.
In one month, fry may reach 0.4 inches (1 cm) in length and around 1.5 inches (4 cm) after 12 months.
|Important: It is not recommended to give fry Daphnia or Cyclops. First of all, they can be too big to fit their mouths. Additionally, large Cyclops may even harm and kill small fry!|
Stimulation for spawning:
- There is no need for a large tank, 1-3 gallon (4-12 liters) tanks are enough.
- Be careful with surface agitation. For example, some filters can disturb the bubble nest.
- Lower the water level to around 6 – 8 inches (15 – 20 cm).
- Raise the temperature to 80 – 84°F (26 – 29°C).
- Enhancing their diet with protein-rich foods (live food).
- Once the abdomen of the female becomes rounded (visibly swell). It means that she is full of eggs. At this point, move her and the male to a breeding To minimize stress for the fish, do it in the dark.
Dwarf Gouramis and Suitable Tankmates
Its tank mates should be all small fish species that are not big enough to eat or harass them, such as:
- Neon Tetras,
- Cardinal Tetras,
- Pygmy Cory,
- Danio rerio,
- Harlequin Rasboras,
- Clown Killifish,
- Least Killifish,
- Otocinclus, etc.
Do not keep Dwarf gouramis with dwarf shrimp.
Personally, I would never recommend keeping Dwarf gouramis with shrimp, especially if you have high-priced shrimp or plan to breed them.
These fish are predators and will consume anything that fits in their mouths. Therefore, they will definitely eat shrimplets. Furthermore, even adult shrimp, after molting, might end up on their menu.
Of course, heavily planted tanks will provide some protection for the shrimp. However, in the long run, it will be a bad idea anyway.
When it comes to the compatibility of freshwater snails and Dwarf gouramis, opinions can vary.
From my experience, I’ve never seen them interested in eating snails. At most, they might nip at the snails’ antennae occasionally, but that’s about it. They often just ignore them.
Nonetheless, you can find stories online where Gouramis consumed snails. Some people even recommend them for controlling snail populations.
Well, I don’t really believe it.
- Large and/or aggressive, and/or boisterous fishes (Cichlids, Large barbs, Goldfish, etc.). Do not keep them with long-finned fish as well (Angelfish, Betta, etc.)
- Keep them away from all types of crayfish and most types of freshwater crabs.
Problems Associated With Dwarf Gouramis
- Diminished Quality: Unfortunately, the high popularity of this species has had a negative impact on its overall quality. To get more money and profit, mass production facilities have been using various types of additives and stimulants for many years. As a result, we have a significant decline in quality.
- Dwarf Gourami Iridovirus (DGIV): There is a widespread epidemic of DGIV, a highly infectious Megalocytivirus species, which has proven to be untreatable. Research in Australia in 2006 found that a considerable percentage of dwarf gouramis coming from the Asia market carried this disease.
- Overbreeding and inbreeding: Inbreeding is the mating of closely related (genetically) Dwarf gouramis. It is intentionally practiced to create genetic uniformity to get a specific color or pattern. The downside of this method is that it weakens their immune systems and makes them more prone to diseases.
- Health Issues: Due to compromised immune systems and stress-related factors, keeping this species often leads to health issues, and these problems can frequently prove fatal.
Given these concerns, some pet shops have stopped stocking them due to difficulties in obtaining healthy or disease-free stock.
In my opinion, finding a local breeder might be a safer option.
Dwarf gouramis are known for their vibrant colors and distinctive body shapes. They are pretty popular aquarium fish and are often kept in home aquariums due to their relatively peaceful nature and small size.
Nonetheless, before buying these fish, it is important to weigh all the pros and cons because very few resources discuss the potential challenges that can arise when keeping these fish.
These include their skittish nature alongside their aggressiveness and territorial behavior during the breeding season, the potential for plant damage during nest construction, and so on.
- Saha, Shibam, S. Behera, Dibakar Bhakta, Abhrajyoti Mandal, Sanjeev Kumar, and Anandamoy Mondal. “Breeding and embryonic development of an indigenous ornamental fish Trichogaster lalius (Hamilton, 1822) in captive condition.” Entomol. Zool. Stud5, no. 3 (2017): 111-115.
- Poudel, Susmita, B. Shrestha, and S. Lamichhane. “Rearing of Trichogaster lalius in aquaria using different types of feed.” Medicon Agriculture & Environmental Sciences1, no. 2 (2021): 18-36.
- Sahu, Sachin, Shubham Sahu, and Priyanka Sahu. “A note on the biology of Dwarf Gourami, Trichogaster lalius (Hamilton, 1822).” International Journal of Fisheries and Aquatic Studies6, no. 5 (2018): 169-171.
- Sahu S, Datta S. “Effect of water pH on growth and survival of Trichogaster lalius (Hamilton, 1822) under captivity.” (2018).
- Bakshi, Snigdha, S. Behera, Shibam Saha, Abhrajyoti Mandal, Anish Das, Dibakar Bhakta, Anandamoy Mondal, and Priyanka Patra. “Influence of spirulina powder at carotenoids concentration in fin of an ornamental fish Trichogaster lalius.” Journal of Entomology and Zoology Studies6, no. 1 (2018): 870-873.
- Awasthi, Madhu, Pragya Gupta, Farah Bano, and Mohammad Serajuddin. “Effects of photoperiods on the growth performance of juvenile Trichogaster lalius (Hamilton, 1822).” International Letters of Natural Sciences65 (2017).
- Sahu, Sachin, Subhendu Datta, and Parimal Sardar. “Effect of water temperature on feed utilization, growth and survival of indigenous fish, Trichogaster lalius (Hamilton, 1822) under captivity.” Journal of Experimental Zoology India23, no. 2 (2020).
- Dorn, Richard. “Aquarium Culture of Trichogaster lalius.” Copeia28 (1916): 17-20. Harvard
- Galib, Shams Muhammad. “Captive Breeding of Trichogaster lalius (Hamilton, 1822) and Trichogaster fasciata Bloch and Schneider, 1801.” PhD diss., University of Rajshahi, 2015.
- Khadka, Niraj. “Viability of Bredding Colisa Ialia (F. Hamilton, 1822) and Larval Rearing on Different Feeding Regimes.” PhD diss., Department of Zoology, 2019.
- ZUANON, Jener Alexandre Sampaio, Pollyanna de Moraes França FERREIRA, Diogo Magalhães da Veiga MOREIRA, Luiz Thiago Versiani MIRANDA, Ana Lúcia SALARO, Sendy Moreira REIS, and Larissa Ferreira de ARRUDA. “Tolerância subcrônica de juvenis de colisas (Trichogaster labiosa e Trichogaster lalius) à salinidade da água.” Revista Brasileira de Engenharia de Pesca8, no. 1 (2015): 26-33.