Opaline Gourami 101: Care, Size, Diet, Breed, & More | 2023

By: Martin McAdam
Updated: April 11, 2023

The Opaline or double-finned gourami is a striking fish that can add color and interest to the community tank.

Although it has been in the industry for several decades, the cause of its brilliant orange/amber coloration continues to baffle scientists. Opalines are hardy fish that remain colorful their whole lives as long as they are kept in ideal conditions.

The Opaline Gourami is well known for its beautiful markings, but it should be noted that when they are excited or agitated, the blue lines will become dull and grey. This change can also happen during times of stress.

Opaline Gouramis are great for aquarists because they eat brine shrimp and bloodworms without difficulty. These fish may be too large for young, inexperienced aquarists to handle since they can grow relatively large and need plenty of space in their tanks.

Opaline Gourami makes excellent parents because the fry can eat finely crushed flake food from their parents' mouths when they open them for feeding.

This article will cover Opaline Gourami's care, diet, behavior, breed, etc. So keep reading!

Opaline Gourami: Species Summary

Scientific Name:Trichopodus trichopterus
Common Name: Opaline Gourami, blue gourami, and gold gourami, three spot gourami
Family: Osphronemidae
Lifespan:4-6 years
Size:6 inches (15.2 cm)
Care Level:Easy to moderate
Origin:Asia, Burma, Thailand
Social Behavior:Aggressive or Semi-aggressive
Water Conditions:72° - 82° F
Hardness Level:5 to 30 dGH
pH level:6.0 - 8.8
Minimum Tank Size:35 -Gallons
Feeding:Omnivorous; accepts flakes and most prepared foods.

This species makes a great community fish as long as you keep them in tanks that are at least 30 gallons and provide them with plenty of space. Since they originate from brackish water areas, it is essential not to keep them in complete freshwater because this can cause them to die.

Many people report that this is a peaceful species and does not bother their tank mates, but there have been some reports of aggression towards other fish in the tank.

The Opaline Gourami can grow rather large and requires plenty of space for swimming. They should be kept in at least 35 gallons of aquariums with plenty of surface area.

Opaline Gourami: Appearance

Opaline Gourami has large, somewhat triangular bodies almost entirely covered with two rows of overlapping scales. They also have a single dorsal fin and pelvic fins, both of which are edged in black, as well as the tail fin.

Opaline Gourami Appearance

Because of this black edging on their fins, they are sometimes confused with bettas. The fish also have an adipose fin behind their dorsal fin, characteristic of the Anabantoids family.

The male has a larger body and three blue lines running from his head to his tail on either side of his body. His pelvic and anal fins also become iridescent, and he has a large hump on his back.

The male's dorsal, anal, and pelvic fins are edged in black. The male has a significant fleshy growth protruding from his back between the bases of his two caudal fins that house the fish's sperm packets. This is called a gonopodium or spawning rod.

Females lack this pronounced hump on their backs and have four blue lines running down their bodies instead of three. Their adipose fin is much smaller than the male's, and their pelvic fins are more prominent, rounder, and less black-edged.

The eggs will be noticeable beneath her thanks to a large white spot on each egg that holds tiny developing fish.

Opaline Gourami: Size And Growth Rate

Opaline Gourami is one of the more prominent members of the gourami family, commonly reaching 3 to 4 inches. Opaline Gourami can take up to 2 years to reach adulthood, at which time they will begin actively reproducing. Males are 20 times bigger than females when they mature.

Opaline Gourami: Lifespan

Opaline Gourami has a relatively long lifespan of 6 years or more. The Opaline Gourami can live up to 8 years in the proper environment, but since they are often shipped as juveniles and not adults, it is often hard to estimate their lifespan.

Opaline Gourami: Breeding

Males build a bubble nest under floating plants or near the water's surface, where they usually remain all day. If kept in a community tank, the male fish will almost immediately become territorial and chase away any fish he feels is too close to his nest.

He may even attack the female if she comes near it. Females will also become very territorial when they are ready to lay eggs.

Opaline Gourami Breeding

The nests are composed of bubbles that rise from the water's surface. A piece of bogwood or clay pot sunk into the substrate may also be used, but floating plants are best because they allow enough oxygen to reach eggs and young fry.

An incredibly intense bout of courtship precedes nest-building. The male will circle the female with his erect dorsal fin and tail oscillating vigorously.

He suddenly quivers while pressing his mouth against the female's side.

She will try to back away during this, but he quickly follows her and circles around her again with his erect dorsal fin. When ready to mate, the female turns to press her belly against a vertical surface while the male moves behind her.

He then nudges her to coax the female into lifting her tail, releasing his sperm onto her eggs as they are released from their white spot.

Opaline Gourami: Gestation Period And Pregnancy

Opaline Gourami is pretty challenging to breed. They require an environment of both fresh and saltwater for reproduction because they are part of the Anabantoidei suborder, which primarily lives in freshwater but needs to breathe surface air.

The fish can be bred in either soft or hard water, but it should have a salinity of 1.005 since these fish originate from brackish water areas. They require a temperature between 74° to 82°Fahrenheit. If the water is too cold, they may not spawn.

The eggs will hatch in about 24 hours, at which time they should be moved to another tank with clean, aged water that has been conditioned with small amounts of salt and a little aquarium water from the tank in which they were spawned.

Opaline Gourami Behavior And Temperament

Juvenile Opaline Gouramis are generally peaceful fish but can become aggressive when fully grown. When they are in their breeding mode, they become territorial and may attack other tankmates if they feel threatened or stressed.

It's best to keep only one pair of Opaline Gourami in the same tank to avoid aggression. If you decide to put multiple pairs in one tank, be sure the tank is large enough for them to establish their territories and that there are plenty of hiding spaces for each pair.

It's important to note that Opaline Gouramis will not coexist peacefully with other gourami species that look similar.

Opaline Gourami: Food & Diet

Opaline Gourami is a very hardy fish but has some special dietary requirements. Its labyrinth organ allows the fish to breathe atmospheric air to survive in heavily silted or murky water.

Opaline Gourami Food & Diet

As these are primarily surface-dwelling fish, they need food that floats at the surface to easily reach it to avoid injury from sharp rocks or other fish that may want to feed on them.

Opaline Gourami is Omnivorous and will readily consume algae wafers, fresh vegetables, and live plants such as Anacharis or water sprite. They also eat mosquito wrigglers and brine shrimp.

Opaline Gourami can also be fed sinking pellets or wafers to ensure their long, thin bodies do not become deformed as they grow.

They will also appreciate some frozen or live brine shrimp or bloodworms. Aquatic plants will make up most of their diet, but you can supplement with brine shrimp, water fleas, daphnia, and tubifex. Like most fish of this species, live foods are best to ensure optimum health.

Opaline Gourami: Care

The opaline is a peaceful fish that will not bother any tankmates unless it is the breeding season when the male becomes aggressive towards all other males and can even become territorial to its reflection!

Opaline Gourami Care

It should be housed in a well-planted aquarium with soft, slightly acidic water. Their natural habitat is in slow-moving, heavily silted, warm water. They can survive in a temperature range of 72° to 82° Fahrenheit.

Opaline Gourami: Tank Size

When choosing a tank for your Opaline Gourami, remember that they are active swimmers and need plenty of room to swim.

This fish is best kept singly or as a pair, since it becomes aggressive towards other fish during breeding. A minimum-sized aquarium for Opaline Gourami would be 35 gallons with thick vegetation.

Opaline Gourami: Water Conditions

The Opaline Gourami is a freshwater fish requiring slightly soft water. The required pH levels for Opaline Gourami should be kept in the 6.0 to 8.8 range, and the temperature should be the same as other tropical fish, between 72° to 82° Fahrenheit.

Be careful when introducing this fish into your tank that has not been established for at least six months. It would be best to acclimate this fish by floating the bag in your tank for 45 minutes to ensure that the temperature and pH levels closely match.


Decorations should be heavy and include lots of plants. They are known to be weeders, so it's best to use dense plants such as Java moss instead of thin-leaved varieties like Java fern.

Your Opaline Gourami should be housed in a well-planted tank with soft water. They are excellent swimmers who can be kept with other peaceful fish such as angelfish, harlequin rasboras, and rainbowfish.

Water Changes

Like most fish, Opaline Gourami will do best when the water in their tank is changed by 10% every two weeks. Since they are sensitive to organic wastes, you must perform these changes weekly to keep them healthy.

Remember not to clean the gravel with tap water during your weekly cleanings, but instead, use a gravel cleaner to avoid exposing your fish to tap water.

Water Filter

A canister filter will keep your tank clean and healthy with minimal maintenance. A sponge pre-filter over the intake tube of the filter will ensure that any smaller fish are not sucked into the filter, injuring or killing them.


You should use an under gravel heating system at a depth of three-quarters of an inch with no more than four tubes. This heater works by heating the gravel portion, which warms the water before it reaches the surface.

A thermostat is recommended for safety purposes because you can guarantee that temperatures will stay within acceptable levels.


A 20% water change every two weeks should keep your tank healthy and free of organic wastes that can cause your fish problems. Be careful not to change the water immediately, but do it over two days to not shock your fish.


Vacuuming is one of the essential tasks of a fishkeeper. Keeping your tank clean not only ensures healthy water but also helps keep your fish from becoming ill or being exposed to disease organisms, which can be deadly.

Your gravel siphon should have a mesh bag over the intake tube to remove waste and small particles without harming the little fish.


Your Opaline Gourami is a stout, large fish with an upturned mouth at the front of its face. It's best to use sand in your tank rather than gravel because it's softer on their mouths, allowing them to sift through it more easily.

Planting the sand with some aquatic plants will help keep it clean and healthy for your fish. They need a bottom that is sand or fine gravel bottom to sift through, and their tank should also have enough shelter to go under the rocks and plants when they feel like it.


Since your Opaline Gourami is a nocturnal fish, low-wattage bulbs will give them the light they need. Eight to 10 hours of lighting per day should be fine for most species of this type.

Opaline Gouramis prefer dim lighting, so you should use floating plants in your tank to add cover and shelter.

Tank Region

Most fish like to have a place to go when they need to escape. The good idea is to provide an overhang or rock where you can create some shade, allowing your fish to hide when needed.

Nitrite And Ammonia

Nitrite and ammonia readings in the tank should be no higher than 0.2 ppm at any time, so having a sound filtration system is essential.

The best way to keep your water healthy is by doing frequent water changes every two weeks, vacuuming the gravel regularly, and cleaning filter sponges regularly. Because Opaline Gourami produces a lot of waste matter in the water, it's essential to top off their tank regularly to keep oxygen, ammonia, and nitrite levels at acceptable levels.

The best way to keep your water healthy is to invest in a system that has a biological filter, such as a canister filter.

Oxygen Levels

Opaline Gourami is native to the warm, still waters of Asia. Because they don't have a swim bladder for buoyancy, they can become distressed when oxygen levels drop too low. You should aerate the water in your tank to keep oxygen levels above six ppm at any time.

Stress Coat

Adding a stress coat solution to your tank can help protect it from things like ammonia and nitrite spikes, common in new tanks. A stress coat will also help protect your fish from stress and disease, allowing them to stay healthy for a longer time.


Keeping your water levels topped off with fresh, clean water is essential. Top-offs help maintain the chemical balance of the tank by replacing what's lost through evaporation or filtration. This will also allow you to test for ammonia and nitrite spikes so that changes in the tank environment can be addressed quickly.


Whether you decide to use live plants or artificial plants, it's important to remember that they are essential to the health of your fish. Plants provide shade and shelter for smaller fish while offering an aesthetically pleasing look to your tank.

Nothing is living in the tank without plants but fish, which can detract from its appeal.


Opaline Gourami can live in brackish and freshwater, though it's healthier in freshwater. The specific gravity should be around 1.003 to 1.005 for optimal health, but the salinity shouldn't be much higher than 1.005, or else your fish will die.

Opaline Gourami: Common Potential Diseases

Opaline Gouramis are prone to the same diseases as most freshwater fish, such as ich and fin rot. If they're stressed, their immune system won't be able to fight off the diseases.

Mortality can be high with this species because of its inability to survive in brackish water or saltwater environments. The problem is that these conditions don't have enough ammonia or nitrites.

The best way to avoid disease is by keeping your fish in an environment that provides clean water, proper food, heat, and space. It's also important to quarantine new fish before adding them to your tank so you can monitor their health.

Opaline Gourami: Treatment For Diseases

Proven medications for diseases include formalin, malachite green, methylene blue, and salt. Copper can also treat ich but is toxic to plants and invertebrates (including the Opaline Gourami).

It's essential to ensure you're using proper dosage measurements when treating your fish for diseases. Improper dosage can either cause a treatment to fail or, in the case of copper treatments, damage your tank environment and denigrate the health of your fish.

However, medication isn't recommended, even if your fish is ill or has the disease. Treating with medication not only harms the good bacteria that are living in the tank, but it also affects your fish's natural immune system. If your fish does become sick, it is best to treat it with a water change and remove the sick fish from the tank.

Other Helpful Tools For Opaline Gourami

  • Water conditioner: A water conditioner is used to treat tap water before it's added to the fish tank since many city glasses of water contain chlorine or chloramines that must be neutralized for fish health.
  • Fish vitamins: Fish vitamins are put in with regular water changes to keep your fish's immune system in good shape and promote healthy, beautiful fish.
  • Quality of fish food: Quality of fish food not only should you give them a balanced diet with things like parasites and algae in mind, but you should also provide them with the appropriate amount of protein for their size.

Opaline Gourami: Acclimation

When you first get your fish, it's advisable to let them adjust slowly to their new tank. After getting them home, net your fish from the bag and place it in a smaller container with water from the store. Float the bag in the tank for 20 minutes before releasing your fish into its new home.

This will give it time to become acclimated to the temperature and chemistry of the water, making it less stressful.

Opaline Gourami: Tank Mates

Opaline Gourami can be kept with larger peaceful fish such as angelfish, rainbowfish, and harlequin rasboras. They can also be housed in community tanks when young but will become aggressive towards other fish if they pair off to breed during the summer months.

As with any fish kept in a community, choosing their tank mates is essential. The Opaline Gourami is peaceful and enjoys the company of other fish who don't nip at their fins or try to eat them.

They can be kept with another gourami, such as the flame and blue gourami, and many different types of freshwater fish.

How To Deodorize Your Tank?

Occasionally, tanks can develop an unpleasant smell or cloudy water due to various debris or other materials in the tank environment. An easy way to eliminate an unpleasant smell or cloudy water is by adding peat moss or activated charcoal to your filter - they'll remove these particles, and the smell will dissipate.

Advantages Of Having Opaline Gourami In Your Tank

  • Beautiful: They are beautiful fish with large flowing fins, deep colors, and long elegant bodies.
  • Large: They are relatively large, so they can keep smaller tanks open for other purposes.
  • Decorative: Their bright colors will catch your attention, but you should never forget that having brightly colored fish in a tank can harm your fish if it becomes stressed out.
  • Accessible to Feed: Opaline Gouramis are not picky and will accept various food. Because they are omnivorous fish, they can be fed flake or pelleted foods in addition to live foods.
  • Peaceful: They have a peaceful temperament, so you should never have any problems with them.
  • Non-aggressive Fish: Because they are not aggressive, you can place them in a community tank with other fish of similar temperament. You should, however, avoid placing them in tanks with fin nippers or smaller fish because the gourami may pick on them.
  • Easy to Distinguish Male From Female: It is easy to distinguish between the sexes. Males have a pointier dorsal fin, while females have a rounder one. This characteristic can determine if you have more than one fish in your tank because it could only happen through breeding.
  • Compatibility: They can be housed with other peaceful fish that do not nip the fins of the gourami. Avoid keeping them in tanks with aggressive fish or ones that like to nip at their fins.
  • Decorative: Their bright colors will catch your attention, but you should never forget that having brightly colored fish in a tank can harm your fish if it becomes stressed out.
  • Easy to Care For: These fish do not require much care. If you decide on getting them, all you need is a clean tank with good water filtration and adequate lighting, and they should be just fine.
  • Large: They can grow pretty significant, so they can be used to keep tanks open for other purposes.
  • Colorful: Their bright colors can add life and vibrancy to your tank because they will not become stressed out when placed with other peaceful fish with calm temperaments.
  • Fish vitamins: Because they are peaceful, you should be able to keep several of them in a community tank. You do not need to worry about them nipping at the fins of other fish.
  • Anabantidae: This species is part of the Anabantidae family, meaning they can breathe air from the surface and swim in open water instead of hiding among plants most of the time.
  • Saltwater and Freshwater Fish: This species lives in fresh and saltwater, so they can be placed in either a freshwater or saltwater tank. You should, however, always keep them in lightly salted water and not entirely fresh because they originate from brackish water areas.

Disadvantages Of Having Opaline Gourami In Your Tank

  • Large: Since they are large and need a lot of space, you will most likely not be able to keep more than one or two in a tank that is 30 gallons or less, approximately 20 inches long.
  • Surface Air: Since their natural habitat is near the surface, they require a tank with plenty of space near the surface so they can breathe. They will not be happy if you give them no access to the water's surface.
  • Tank Size and Compatibility: Their large size requires a larger tank, and often they cannot be housed in tanks smaller than 20 gallons. Since they are incompatible with many fish, they may not be a good fit for your tank if you already have a whole load of fish.
  • Water Flow: They require a moderate amount of water flow and filtration to keep the water clean and healthy for them to thrive in their environment. If there is too much or not enough water flow and filtration, it can upset their environment and stress them out.
  • Sensitive to Chemicals: If the aquarium has a lot of chemicals, such as chlorine, in the water, it can be harmful to your fish because they come from very soft water areas to begin with. This may harm them if there are too many chemicals in the water.
  • Temperature: If the temperature of your tank gets too hot or cold, they may die because their environment needs to be kept between 74° to 82° Fahrenheit.
  • Tankmates: Since large fish require a lot of space, it is often hard to find suitable tank mates. They can be kept in a species-only tank or with other large fish that do well in their environment.
  • Diet: They are carnivores, so they require a lot of protein. If your tank does not have enough protein and you do not provide them with the proper food, they may become sick or die.
  • Thick Plants: Since they originate from open water areas without vegetation, the best place to live is in tanks with thick plants. It would help if you had enough plants in your tank at least two to three inches so they could feel comfortable in their environment.
  • Light: They should live in a well-lit tank to keep their colors bright and vibrant. These fish are easily stressed out when there is not enough light in their environment, so you should keep them in a tank with at least one light bulb.
  • Hoarder: They are hoarders for plants and can rip up your aquarium plants if they are not kept in tanks where the plants stay close to the top of the water or are very thick. This is because they originate from brackish water and prefer to live in areas that have floating plants.
  • Hard Water Areas: If the pH levels in your tank get too high or low, they can die because their environment requires a much more neutral environment than what most tanks provide for them.


A very hardy fish, the Opaline Gourami is fun in an aquarium with other peaceful species of fish. They can tolerate various temperatures and pH levels, making them ideal for novice aquarists and more experienced hobbyists.

Under challenging locations where the water quality isn't top-notch, it's essential to make sure you are checking the pH levels in your tank regularly.

In conclusion, if you are looking for a great fish to add to your aquarium and have the space to house Opaline Gourami, try it.


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