Betta Macrostoma FAQ (A Look at the Brunei Beauty)

Betta Macrostoma is rare to find but is similar to Betta splendens in care, requiring tropical water temperatures, soft and slightly acidic water, and a varied carnivorous diet. They are also best housed in breeding pairs in tanks of 20 gallons and can live with their young if the tank is well-planted.

In this article, we will look at the origins of Betta Macrostoma, how they look, how to differentiate between male and female Betta Macrostoma, and how to care for them.

What Other Names Does the Betta Macrostoma Go By?

Betta Macrostoma is also known by the names Spotfin Betta, Tail Spot Betta, Ikan Pelaga Brunei, and Brunei Beauty.

Where Does Betta Spotfin Macrostoma Originate from?

Betta Spotfin Macrostoma originates from Southeast Asia.

More specifically, they originally live in the inland wetlands of a small country called Brunei Darussalam, on an island called Borneo. This island is a part of Malaysia and Indonesia.

“Macrostoma” literally means “large opening” or “large mouth” because Betta Macrostoma are mouthbrooders, meaning they have exceptionally large mouths and jaws compared to the rest of their body, giving them their unique name.

How Much Does Betta Macrostoma Cost?

Betta Macrostoma costs anywhere between $60 and over $900.

Aquarium Fish Sale has a page for Betta Macrostoma, the price of a male and female pair being $339.99.

You will also need a few other items, such as a 20-gallon tank, slow current filter, heater, thermometer, biotope decorations, varied fish food, and a water testing kit, which can cost around $200 – $400 as a start-up, and then minimal costs to upkeep food, botanical and plant stocks.

After the initial setup, a healthy fish tank won’t cost more than a few dollars every year to ensure you have enough food, botanicals, fresh filters, plant supplements, and plants to keep the tank thriving.

What is the History of Betta Macrostoma?

Originally discovered in Brunei Darussalam and North Sarawak, Malaysia, the Betta Macrostoma is listed on the IUCN Red List as a vulnerable species due to the destruction of its habitat. This makes Betta Macrostoma incredibly rare in the wild and almost impossible to find in captivity.

Betta Macrostoma that is eventually found or is available for purchase in captivity usually sells for a high price, making Betta Macrostoma the most expensive and rare Betta in the entire genus.

How Big Are Betta Macrostoma?

Betta Macrostoma, in healthy and ideal conditions, can grow anywhere between three and a half to four and a half inches long.

What Is The Lifespan Of Betta Macrostoma?

Betta Macrostoma can live anywhere between three to ten years. For a longer life, Bettas should be well-taken care of in optimal water parameters and in large tanks with small water changes and lots of plant life. 

What does Betta Macrostoma Look Like?

Betta Macrostoma has an elongated, torpedo-shaped body with the top fin starting further down along the spine, and the dorsal and tail fins are short and round. The back fin is only half as long as Betta splendens veil tails but shares the same width.

The Spotfin Betta’s name comes from some male Bettas having a spot on their top fin. Males are typically more colorful with multicolored fins, patterned occasionally with a spot, and look similar to Chinese brocaded fans.

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How to Tell the Difference Between a Male and a Female Betta Macrostoma?

Males are colorful, while females have two stripes going along their bodies.

Male Betta Macrostoma tends to be more colorful than female Betta Macrostoma, and when breeding, males’ colors become more brilliant shades of black and orange to red shades. 

Female Betta Macrostoma usually has horizontal bands on the sides of their body, whereas male Betta Macrostoma does not. It may also be possible to confirm if a betta has ovaries by spotlighting.

You can learn more about the difference between female and male Betta Macrostoma, and their needs, with an informative article by IBC Bettas.

What is the Care Level for Betta Macrostoma?

As Betta Macrostoma are rare and endangered species with delicate needs, they are best suited for expert fish owners. Those who do own Betta Macrostoma are encouraged to breed them and help increase the numbers of Betta Macrostoma.

Are Betta Macrostoma Aggressive?

Betta Macrostoma, unlike their cousin the Betta splenden, are relatively peaceful. Unlike Betta splendens, a male and female Betta Macrostoma can live together long-term.

Can Betta Macrostoma be Housed in the Same Tank?

A male and female Betta Macrostoma can be housed in the same tank, and for these species, due to their unique temperament, it is recommended that they be housed in a male and female pair.

What are the Key Differences Between Betta splendens and Betta Macrostoma?

Here are some key differences between Betta splendens and Betta Macrostoma:

  • Male and female Betta splendens pairs cannot be housed together for longer than the breeding season, whereas male and female Betta Macrostoma can be housed together as life-long partners.
  • Betta splendens are bubble nesters, whereas Betta Macrostoma are paternal mouthbrooders, highlighted by their large mouth and jawline.

What is Betta Macrostoma Paternal Mouthbrooding?

Betta Macrostoma Paternal Mouthbrooding is when the male takes the new eggs and holds them in his mouth to incubate them. Incubation takes an average of 14-35 days.

Ocean Conservancy goes in-depth on this topic in their article, saying mouthbrooding is an effective strategy in the wild as the parent protects the eggs from other fish or predators from eating them. This makes the eggs more likely to survive their incubation time and hatch. 

Incubation is also difficult as the process does not allow for the male Betta to eat anything during the incubation period.

How Do You Breed A Macrostoma Betta?

Betta Macrostoma is the most comfortable in soft water with a pH below 6; these water parameters will encourage spawning. When spawning has started, and during the incubation period, the fish should be disturbed as little as possible to ensure a successful spawn.

Normally it is the female who initiates spawning. During spawning, the male will embrace the female. She will lay the eggs that he will fertilize, and this process can be repeated for between two to five hours.

When the spawning is done, both the female and male Betta Macrostoma will gather the eggs that are along the floor of the tank in their mouths. The female will pass the eggs to the male, and the male will gently hold them in his mouth until they are hatched.

Incubation varies depending on the water temperature, with some sources saying 30 and 35 days or 12 and 17 days. 

During the incubation period, both the male and female Betta Macrostoma should not be disturbed and should be left alone together in their tank in a quiet environment. The female should be left in the tank along with the male, and while the female can be fed, the male should not be fed. Feeding the male may cause him to accidentally swallow the eggs.

After 14 days, the female can be removed from the tank. Once the eggs hatch, the male can also be removed. In any given spawn period, between 10 and 20, Betta Macrostoma offspring will hatch. About 15% of these will be male.

How to Care for Betta Macrostoma Offspring?

Freshly hatched Betta Macrostoma offspring are about 0.2 to 0.39 inches long. They are fully independent the moment they are born and will need to be fed an offspring-friendly diet by the tank owner.

Foodstuff examples that Betta Macrostoma offspring enjoy are micro worms and vinegar eels.

In large tanks of 20 to 40 gallons, with lots of plants and an excellent filtration system, it is also acceptable to keep the Betta Macrostoma parents and offspring together for up to six months. 

As long as the tank has lots of hiding places and dense plants, Betta Macrostoma offspring can avoid pursuit and can be removed from the breeding tank when they are large enough to be caught with a net.

Young Betta Macrostoma releases a growth-inhibiting hormone in the water that will slow the growth of other Betta offspring, so it may be necessary to do a daily 10% water change to keep the water pristine.

Young Betta Macrostoma are about two inches in length when they reach six months if they’ve received an adequate, nutrient-rich diet and a clean, well-kept tank. When they reach six months, it may be possible to identify which are males and which are females. At that time, it is recommended to separate the genders.

Taking care of your Betta can be tricky, but it doesn’t have to be. Click here to read an article with everything you need to know about Betta fish care.

How Do You Care for Betta Macrostoma?

Does Betta Macrostoma Need to be in a Pair?

As Betta Macrostoma are peaceful and social and are not compatible with any other tank mates due to either trying to eat their tank mates or being stressed if their tank mates are too big, Betta Macrostoma is healthiest in a single species tank with a breeding pair.

How Large of a Tank Does Betta Macrostoma Require?

A breeding pair of one male and one female Betta Macrostoma requires at least 20 gallons, whereas a small school or group of Betta Macrostoma requires 50 gallons.

Also, ensure that whichever tank size you go with that has an adequate, closed, and tight-fitting lid. Betta Macrostoma are strong jumpers and will try to jump out of their tank.

What Kind of Water Does Betta Macrostoma Require?

The water should be at a temperature range of 75-79 degrees Fahrenheit (24-26 degrees Celsius), a pH between six and seven, and a water hardness of 1-10 dKH. Ensure with frequent water checks that the water pH does not go over seven and is maintained with very little fluctuations in the pH.

How Do I Adjust the Water pH to Make it More Acidic for my Betta Macrostoma?

There are four ways to adjust the water’s pH to make it more habitable for Betta Macrostoma: driftwood and botanicals, plants, sponge filters, and small water changes.

Driftwood and botanicals, when added to the tank, not only provide natural shelter for the Betta Macrostoma but also release tannins in the water and lower the pH naturally over time. 

Living plants, when largely populating a tank, contribute positively to the tank’s ecosystem, absorbing ammonia and nitrates.

A sponge filter will mimic the Betta’s natural habitat of a slow-moving river with its slow current, and the sponge will allow for beneficial bacteria to grow while cleaning the water.

Partial water changes of 25% once a week allows for clean water to be introduced in a small amount to not disturb the water parameters but to also keep the tank clean.

Fish Laboratory goes into more detail on Betta Macrostoma care in their article here.

What is Necessary to Purchase Along with Your Bettas and Tank?

Here are some other items you will want to have on hand along with your Bettas and tank:

  • Water filter
  • Submersible heater
  • Thermometer
  • Water testing kit
  • Frozen food
  • Freeze-dried food
  • Weathered or Malaysian driftwood
  • Natural decorations such as stones
  • Planting substrate
  • Substrate topper (sand)
  • A variety of aquatic plants

How Do You Create a Biotope Tank for Betta Macrostoma?

Fill your tank with natural items such as driftwood, plants, and botanicals, and lightly stain the water with tannins to re-create an authentic natural habitat for your Betta Macrostoma. 

The Betta Macrostoma’s natural habitat includes shallow rivers and streams in dense jungles. The river is filled with the organic decomposition of vegetation, branches, and plant matter that are used as hiding places.

To create a biotope, or natural habitat, such as this would be ideal for the longevity and overall health of your Betta Macrostoma.

As there is a natural canopy in the habitat of Betta Macrostoma’s original home, and the thick vegetation in the river also provides cover from the sunlight, dim to low lighting is recommended for the Bettas. 

Too much lighting will be a stressor point for your Betta. To provide more of a peaceful environment, give your tank low lighting, a few floating plants, and driftwood to provide hiding places. 

Another way to dim the tank is to put a shader or dark background on the back or on the three sides of the tank to block out excessive light from outside.

One other way to dim the tank is to add a tannin extract from almond or oak leaves to dye the water, which is also found in its natural habitat. This will also provide a more secure and peaceful environment for the Bettas.

What Types of Plants Can be Added to a Betta Macrostoma Tank?

Any freshwater plant that can flourish in low lighting, high acidity (low pH), and tropical temperatures of 70 to 80 degrees Fahrenheit will make a great addition to your tank. Some examples include:

  • Java fern.
  • Java moss.
  • Anubias.
  • Frogbit.
  • Water Sprite.

Java fern is an easy plant to care for as it can attach to any piece of driftwood or rock, with long leaves that provide ample places for a Betta to hide.

Java moss provides a comfortable bed that your Betta can lie in.

Anubias have teardrop-shaped leaves that can act like natural hammocks, supporting the weight of your Betta Macrostoma if they lie on it.

Frogbit and Water Sprites are floating plants that grow long, thin roots. Not only do they help to process the water, but they provide shade and hiding spots for your Bettas.

What Tank Mates Can Betta Macrostoma Have?

Even though Betta Macrostoma are more peaceful than their counterpart, the Betta splendens, they are still territorial and are best housed with their species and no other tank mates.

What Does Betta Macrostoma Prefer to Eat?

Preferring a high protein diet, Betta Macrostomas are Omnivores. They may be pickier than other Bettas and may not accept traditional betta pellet food. There are other options of food available, such as freeze-dried, frozen, or fresh food such as:

  • Shrimps.
  • Black worms.
  • Bloodworms.
  • Glass worms.
  • White worms.
  • Mosquito larvae.
  • Brine shrimp.
  • Krill.

What Does Daily, Weekly, and Monthly Care Of Betta Macrostoma Look Like?

Daily, Weekly, and Monthly Betta Macrostoma Care Guide

FeedingGive 1-4 pieces of food.  
25% water change Add fresh, de-chlorinated water. 
Trimming plants  May by bi-monthly, depending on the speed of your plant growth.
Adding botanicals  Add in new ones and remove old ones as they decompose.
Adding tannins As the water is filtered, tannins will need to be added as desired. 
Filter washing  Filter media should be washed in dirty tank water to remove debris. Replace as per product instructions.
Water testing  An established tank only needs water testing once a month.


Betta Macrostomas are a rare species that are fascinating to learn about, from things such as their breeding habits, to how their offspring grow and how Betta parents interact with each other. If you own a Betta Macrostoma, it is good to know as much as possible. This will allow you to give your Bettas the best, most ideal life as your pet and companion.