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Opaline Gourami: Everything You Need To Know

Opaline Gourami: Everything You Need To Know

The Opaline Gourami is a beautiful and peaceful freshwater fish native to Southeast Asia. It is a popular choice among both beginners and experienced aquarists given its peaceful nature, attractive coloration, and ease of care. It is also a specially bred fish, which gives it a unique look. 

The Opaline Gourami (also known as Trichopodus trichopterus or marbled Gourami) is a hardy fish that survives in both community and single-species tanks. It’s a great choice for anyone looking for a unique and interesting addition to their aquarium, especially for beginners.

Although Opaline Gourami are easy to take care of, they still have guidelines on what will help them thrive. Below, we will talk about everything you need to know about Opaline Gourami, including how to care for it, what environments it thrives in, and how to monitor for illness.

Opaline Gourami Overview & Habitat

  • Common name: Opaline Gourami
  • Scientific name: Trichopodus trichopterus
  • Care level: Easy
  • Size: Grow up to 6 inches (152.4 mm)
  • Life Span: Up to 4-6 years
  • Temperament: Peaceful
  • Diet: Omnivore
  • Minimum tank size: 35 gallons (132.48 L)
  • Tank level: Top dweller
  • Water temperature: 73-82°F (22.77-27.77°C)
  • Water pH: 6.0-8.8
  • Water hardness: 5 to 35 dGH

The Opaline Gourami are bred in captivity. Their natural habitat includes slow-moving dark waters, where they eat zooplankton, crustaceans, and larvae. They are bred for their unique coloring, a beautiful silvery blue and almost iridescent in some lighting. Since this fish is easy to care for, it makes a great addition to any beginner tank! 

The Osphronemidae Species

The Opaline Gourami belongs to the Osphronemidae species, which includes fighting fish, gouramis, pikeheads, and many other subspecies. They are also Labyrinth fish, meaning they can absorb oxygen from the air into their bloodstream. Therefore, they occasionally need access to the surface to get air occasionally. 

Opaline Gourami Appearance & Size

The appearance of an Opaline Gourami is a vivid, silvery blue with a marble-like pattern.

They usually grow up to 6 inches (152.4 mm) long if kept in a tank of the appropriate size. The size can also depend on genetics, as the Opaline Gourami is a specially-bred fish. Nevertheless, you should keep the maximum size in mind when planning your aquarium to ensure the fish have enough space. 

Difference Between Males and Females

Male Opaline Gourami are slimmer and smaller than females and have a longer pointed dorsal fin. Females on the other hand have rounder bellies and their dorsal fin is shorter.

Opaline Gourami Personality & Behavior

The Opaline Gourami has a peaceful and gentle temperament, making it an ideal choice for both community and single-species tanks. It is an active species that enjoy swimming around in the open water and exploring its environment. It rarely shows any signs of aggression unless it becomes territorial with other male fish

Opaline Gourami Average Lifespan

The more you cater to the needs of the Opaline Gourami, the longer you can expect to have it around! If properly taken care of, your Opaline Gourami can live for 4-6 years. This means you will need to get the proper tank size and mates, take care of the water, and feed them properly. 

Opaline Gourami Care & Tank Set Up

Although the Opaline Gourami is a great beginner fish, you still need to be on top of its tank needs, otherwise, you risk your fish getting sick and dying. 

Taking precautions and learning about the ideal environment will set you and your Opaline Gourami up for success in the long run.

Aquarium Nitrogen Cycle

The nitrogen cycle is one of the most important aspects of fishkeeping.

A common mistake for beginners (new tank syndrome) is either not knowing about the nitrogen cycle or not keeping it in mind when maintaining the water.

What Is An Aquarium Nitrogen Cycle?

The nitrogen cycle is the process by which beneficial bacteria convert fish waste and uneaten food in the aquarium into less harmful substances. The cycle is crucial for maintaining a healthy and stable environment for fish and other aquatic animals.

In new aquariums, there may not be enough bacteria to break down fish waste, resulting in an unhealthy buildup of ammonia and nitrite. This is not visible to the naked eye, so it’s important to regularly test the water with a kit to ensure the smoothness of the nitrogen cycle.

What Happens If I Don’t Complete A Nitrogen Cycle?

Failing to complete regular nitrogen cycles can lead to the accumulation of harmful substances like ammonia and nitrite. These substances can cause stress and damage to fish, leading to health problems and if left unchecked it will eventually kill everything in your aquarium.

By maintaining a healthy nitrogen cycle, you can ensure a long and healthy life for your fish.

Tank Size 

Provide ample hiding places and space in the tank for the Gourami to make them feel safe and comfortable. A tank of 35 gallons (132.48 L) minimum will be the best choice for your Opaline Gourami if you keep them on their own. 

In general, plan on a gallon of water for every inch of fish, and choose a tank that is long rather than tall so that your fish can easily swim up to the surface.

If you add the Opaline Gourami to a tank with an existing community, you’ll need something much larger that gives these fish adequate space. One rule of thumb is to plan on a gallon of water for every inch of fish.

Water Parameters

  • Water temperature: 73-82°F (22.77-27.77°C)
  • Water pH levels: 6.0-8.8
  • Water hardness: 5 to 35 dGH

Water Temperature

The Opaline Gourami prefers a temperature between 73 and 82°F (22.77-27.77°C), as this replicates their natural environment. This species is tolerant of a wide range of water parameters, which makes them hardy fish compared to other species. 

Water pH Levels

The proper PH for an Opaline Gourami is 6.0-8.8. Make sure to keep PH strips handy to test the tank’s conditions often. It is important to keep the water stable to ensure a healthy environment for your Gourami.

Tank Maintenance 

Regular water changes can help keep the water clean and the pH stable, which will help to keep your Gourami healthy and happy. In addition to frequent water changes, provide plenty of oxygen in the tank, as this species is an air-breather and needs access to the surface to take in oxygen.

What To Put In The Tank

The Opaline Gourami like to hang out in the top half of the tank, as they will come up to the surface for air. When they are not visiting the surface, they will enjoy the hiding spots to rest, similar to their natural environment. 

Below, we will discuss some of the best tank elements to keep in mind for the Opaline Gourami so that they can enjoy their new home. 


The best substrate for an Opaline Gourami is a sand and gravel blend. Consider choosing darker colors as the species is used to a darker environment. This combination will also give you a firm base for vegetation in your tank. 


You do not need too many decorations for the tank, as the Opaline Gourami will often swim around it. Vegetation will be enough, but remember what decorations other tank mates may want if you decide to get some. As long as it is not invasive to the Opaline Gouramis space, it should be fine! 

You could consider floating plants as a decoration, as they block out some light, allowing for a darker environment. Just like the other vegetation in the tank, make sure the floating plants do not block the way for your Opaline Gourami to get air! 

Ideal Plants

Since Opaline Gourami is very active and needs space to reach the surface, consider getting a few plants that will not take up too much space in the tank. Overcrowding with plants can make it more difficult for Opaline Gourami to get back to the surface when they need more air. 

Some great live plant options include: 

Be sure to trim any vegetation that could block access to the surface. The purpose of vegetation for Opaline Gourami is to give them places to relax without taking up too much swimming space. 


Because Opaline Gourami is a tropical species you will need a good aquarium heater to help maintain a stable water temperature. It’s important to choose a heater that is easy to adjust and has a reliable thermostat to ensure accurate temperature control.


Opaline Gouramis are sensitive to noise and prefer a peaceful environment. Sponge filters are an excellent choice, as they provide gentle filtration that helps keep them calm and relaxed.

Opaline GouramiI Tankmates

When finding tank mates for the Opaline Gourami, choose fish with a similar size and temperament. The Opaline Gourami can become territorial if they feel threatened or the tank becomes crowded. Ideal tankmates for the Opaline Gourami include: 

Tank Mates To Avoid

Avoid adding aggressive fish or smaller Gourami to the tank. Since Opaline Gourami eats shrimp and larvae, smaller creatures can become an issue. 

Moreover, because opaline gourami can be so territorial, I wouldn’t suggest overly “peaceful” fish, such as the chili rasbora. These fish will be easily bullied and likely eaten by a bigger more territorial fish such as opaline gourami.

I don’t think it’s a bad thing to only have an aquarium full of your opaline gourami. Yes, sometimes it can be nicer to have a diverse aquarium, but it’s also nice to not have to referee between a lot of fish. If your opaline gourami doesn’t seem to do well with any other breeds, it’s okay to keep them alone.

In this case, to add brightness and some diversity to your tank, I’d highly suggest adding lots of different plants to your ecosystem. You can also add some more passive “pets”, such as moss balls.

Opaline Gourami Food & Diet

Opaline Gourami is an omnivore and should be fed various foods, so a combination of foods is recommended to ensure a balanced diet. Some of the best foods to feed your Opaline Gourami Include: 

  • Bloodworms
  • White Worms
  • Brine Shrimp
  • Blanched Lettuce
  • Algae-Based Flake or Pellet Fish Food

Feeding several small meals throughout the day is recommended, as this species can overeat and become prone to bloating. It is also important to remove any uneaten food to keep the water clean and prevent water quality issues.

Breeding Opaline Gourami 

Since Opaline Gourami is bred in captivity, it is easy to breed at home. You need a shallow breeding tank to make their bubble nest for the eggs on the surface. Keep the water temperature warmer at 80 degrees or so for the best results. 

High-protein snacks can help start the breeding process. The female Opaline Gourami will release her eggs once the male completes the bubble nest at the surface of the breeding tank. Remove the female and leave the male Opaline Gourami to guard the eggs until they are free swimming on their own. Once big enough, they can be introduced back into the tank. 

Opaline gourami shouldn’t be crossbred. 

Gourami Common Health Issues

Opaline Gourami is a freshwater fish, so it can be affected by many freshwater fish diseases. Overcrowded tanks with poor water conditions can accelerate or cause these diseases. 

The most common conditions among these fish include: 


This is a parasitic infection also known as white spot disease. You can tell your Opaline Gourami has ich if they develop little white spots on the surface of their scales.

Ich Symptoms

  • White spots: The most noticeable symptoms are white spots that appear randomly scattered across the body, fins, and gills.  Keep in mind, this may start out as one single white spot, so monitor your fish closely.  If the spots increase and start spreading, it will almost certainly be Ich.
  • Keep in mind if your fish are bright colors, spotted patterns, or have big fins, it is going to be significantly harder to detect the white spots.
  • Breathing Faster: When Ich infects the gills, it can make it harder for your fish to breathe. When this happens it causes their gills to work harder and move faster than usual to compensate for the difficulty in taking in oxygen.
  • You may even notice your fish rise to the tank’s surface to make use of the oxygen.
  • Lethargy: As the infection progresses, you will notice your fish will become lethargic and move around the tank slower than they normally would.
  • Loss of appetite and color: As the infection progresses, your fish will lose its appetite and in some cases, its color will become paler.
  • Brushing up against objects: These white spots can become very itchy.  When this starts to happen you’ll notice your fish start to brush up against objects to relieve the itching.

Ich Treatment

Test water quality: You need to ensure your water quality is in great shape.  Get a good test kit and test levels for pH, Ammonia, Nitrite, Nitrate, KH, and GH. If anything is out of the ordinary, get onto it immediately.

Raise the water temperature: This will shorten the life cycle of Ich. It is recommended to increase the temperature to at least 86 degrees (30 Celsius) and ensure you don’t exceed 90 degrees (32 degrees Celsius). Before you raise the temperature, make sure other species in your tank are able to cope with the increase. 

If you have established that all species can cope with the rise in temperature, only increase it by 2 degrees every twelve hours.  Once you have reached the desired temperature, leave it at this level for at least 2 weeks. After 2 weeks, slowly reduce the temperature back down to its normal state.

Add commercial medications: Sometimes adding medication is your only option. Make sure you:

  • Remove all forms of chemical filtration before adding the medicines.
  • Transfer your fish to a quarantine tank before medicating.
  • Read the directions and use a calculator to work out the dosage required.

Ich Prevention

Ensuring you quarantine all the fish you buy before adding them to your main tank is the best way to prevent Ich.

Hole In The Head Disease

Hole in the head disease, also known as head and lateral line erosion is a common disease in many freshwater and saltwater fishes.

Hole In The Head Symptoms

This disease is characterized by small dark holes or deep pits around the head. These may all be the same color, or vary in color, size, and depth. The primary cause of this disease is stress.

Hole In The Head Treatment

Test water quality: You need to ensure your water quality is in great shape.  Get a good test kit and test levels for pH, Ammonia, Nitrite, Nitrate, KH, and GH. If anything is out of the ordinary, get onto it immediately.

Sufficient diet: Make sure the food you are feeding your fish has been opened within the last 6 months. After this time period, nutrients and vitamins will have significantly diminished.

Manage any bullies: If you have bullies in your tank that are stealing food or nipping at your Opaline Gourami during meal time, it will cause them stress. If you can’t get your bullies to play nicely, it might be time to find them a new home.

Peaceful environment: Opaline Gourami are sensitive to sounds, including filtration systems, sound from a TV or stereo, etc. If your tank is in an area that has a lot of noise pollution, consider placing them somewhere else or provide insulation.

Hole In The Head Prevention

Make sure you provide a healthy, calm, and peaceful environment and deal with any potential stressors.

If your Opaline Gourami does not improve after eliminating all potential stressors, contact your aquatic veterinarian for appropriate treatment.

Opaline Gouramis FAQs

Are Opaline Gouramis Aggressive?

Opaline Gouramis are generally peaceful fish but older males can be aggressive and territorial with other males and smaller fish.

How Can You Tell If An Opaline Gourami Is Male Or Female?

The easiest way to tell the difference between the male and female Opaline Gourami is by their dorsal fin.  The male has a longer, pointed dorsal fin compared to the female. They are also smaller and slimmer. Females have more plump bellies and shorter dorsal fin.

How Big Of A Tank Do Opaline Gouramis Need?

A tank of 35 gallons (132.48 L) minimum will be the best choice for your Opaline Gourami if you keep them on their own.

In general, plan on a gallon of water for every inch of fish, and choose a tank that is long rather than tall so that your fish can easily swim up to the surface.

Wrapping Up

The Opaline Gourami can be a great addition to your tank, especially if you want a fish with vibrant color and a peaceful demeanor. 

While the Opaline Gourami are easier to care for than many species, you still need a large enough tank to make them feel secure. You should also regularly check the water quality and parameters to ensure it meets the standards for this species.

I’m Elle, the founder of FishHQ. I created this website to share knowledge, tips, and inspiration for beginner hobbyists to help them create a healthy, happy, and vibrant environment for their fish to thrive. Read more...