Alex Bell provides a comprehensive care guide for his favourite wild Betta species, the White-Seam Betta (Betta albimarginata).
There's more to Bettas than the common bubble-nesters, Betta splendens, that are found in every local fish store. The white-seam Betta (Betta albimarginata) has always stood out as one of my favourite wild Betta species.
Hailing from the forest streams of Borneo's peat swamps, these small but striking mouthbrooding Bettas captivate with their deep brick-red coloration and iconic high-contrast fin borders. However, seeing them at their best requires more than a standard community aquarium. Mastering Betta albimarginata care involves recreating a specialised blackwater habitat, mimicking the acidic, tannin-rich waters of their jungle home.
Whether you are a dedicated wild Betta enthusiast or a newcomer looking for a unique breeding challenge, this guide covers everything you need to know to keep this wonderful Anabantoid thriving.
All images by Alex Bell unless otherwise stated
White-Seam Betta Fact File
Scientific name: Betta albimarginata
Size: up to 3.5cm (1.4”) with females typically growing a little larger than the males.
Origin: Sebuku River basin, East Kalimantan, Borneo.
Habitat: Shallow forest streams shaded by marginal plants and the overhead canopy. The waters feature leaf litter and a fine silty sediment.
Tank size: 45x25x25cm (18x10x10”)
Water requirements: Soft and acidic with a pH below 6.5 and a hardness below 5°H will work well.
Temperature: 23-28°C (73-82°F)
Temperament: Peaceful and shy, it is not suitable for a busy community aquarium as it will likely be outcompeted. Maintain in a species only tank or alongside small peaceful fish that require similar conditions.
Feeding: A micropredator, hunting for small worms and insect larvae amongst the leaf litter as well as snapping up drifting zooplankton. Offer a varied diet with regular feeds using frozen and live foods to see them at their best.
Availability & cost: Uncommon as their specific requirements makes them difficult to house in typical retail aquariums. Expect to pay around £50 a pair depending on source.
Natural Habitat and Origin
This beautiful Betta species comes from the Sebuku River basin in East Kalimantan, Borneo. They live in incredibly shallow forest streams, measuring just 5cm (2") deep in some places during the dry season.
The streams feature a fine silty substrate, produced from the decomposing materials that fall in from the surrounding forest. Leaves, branches and seed pods tend to accumulate in the slower moving areas of the streams, often amongst the roots of marginal plants. This is the favoured spot for Betta albimarginata.
A typical peat swamp habitat in Borneo - Photo by Shutterstock
Aquatic plants are rare in these waters, the forest canopy and tinted waters from the tannic acids block out a lot of light. However, greenery does feature when the water level rises, inundating the marginal and terrestrial plants.
Appearance and Identification
This is a visually striking species. Mature males display a bold brick red colour across much of the body. The fins have a bright white seam around the edges, with a black band just inside this, framing the bright red fish perfectly.
The males are bold brick red in colour (centre) the females a mottled brown (below).
The Betta albimarginata females display more subdued colours, with a mottled brown appearance. However, some individuals may still possess a white edge to their fins, although it is usually less bold.
Betta albimarginata vs Betta channoides
The snakehead Betta (Betta channoides) is a similar looking species and is part of the Betta albimarginata group. The snakehead Betta also occurs in East Kalimantan, Borneo but it occurs in the Mahakam River basin.
Luckily, there are a few key visual differences for hobbyists to look for to help identify the two species.
- Betta channoides display an almost entirely red dorsal fin, with just a thin white band. Betta albimarginata have a thick white band and a thick black submarginal band.
- The base red colour of B. albimarginata is brick red, in B. channoides it is more of a scarlet red.
- The black submarginal band of the caudal (tail) fin in B. channoides stops before it reaches the top of the fin.
Tank Size & Compatibility
Betta albimarginata are not like your classic fighting fish (Betta splendens). They can share their tank with conspecifics (members of the same species) without a battle to the death ensuing.
For a pair of white-seam Bettas, a tank measuring 45x25x25cm (18x10x10") would certainly suffice. Larger aquariums will even allow you to house a group successfully as unlike some other Betta species, B. albimarginata display relatively mild levels of aggression. Hierarchies may form within the group but serious injury or stress is uncommon in a well decorated aquarium.
You can keep small, peaceful species alongside them which can act as dithers helping to bring the best out of your Bettas. chilli rasboras (pictured above), Sundadanio species, and small characins like ember tetras and pencilfish will all work well.
Gentle but mature filtration will suffice, like that of an air driven sponge filter. These fish do inhabit flowing water though, so the water does not need to be almost stagnant. Critically, the aquarium must have a tight fitting lid, as these fish are brilliant at jumping.
Aquascaping for Betta albimarginata
White-seam bettas can be shy and certainly appreciate a lot of cover and shade in their aquarium. We must keep this in mind when decorating their tank.
While aquatic plants aren't present in their natural habitats, they certainly work great in aquariums, providing a safe refuge. You must, however, pick species that will cope under dim light, as these fish will not enjoy the high intensity lighting required for the demanding species.
Twisted roots and branches can work well for a wild Betta tank, providing plenty of three dimensional structure. The addition of leaf litter and botanicals can further add to the complexity of the habitat.
Woods and botanicals will leach out tannins, staining the water giving a natural blackwater look. These tannins are weakly acidic and will help lower the pH of the water if the carbonate hardness is low, creating the conditions these Bettas thrive in.
Substrate choice is not critical: a fine, inert sand is a cost effective option that works perfectly well. Aquascaping soils have a tendency to remove tannins from the water and are not great for blackwater aquariums. Avoid substrates like coral sands that will raise the pH and hardness of the water as the Bettas will not thrive in these conditions.
Water Parameters
Betta albimarginata live in blackwater streams and are adapted to thrive in the conditions found in these habitats. That means soft and acidic water is a must for their aquarium. Aim for a pH below 6.5 and a hardness below 5°H and your fish will thrive.
In these acidic conditions (below a pH of 6), the typical filter bacteria we are familiar with stop functioning efficiently. Fortunately, the ammonia the fish produce will be present as the less toxic ammonium in these conditions. The concentration of the ammonium can be easily managed with sensible stocking levels, water changes, and floating or emergent plants.
We must, however, be careful when water changing blackwater aquariums. The water we add needs to be acidic as well. Otherwise we may accidentally raise the pH of the tank and the ammonium that is present will shift into the toxic ammonia form, harming our fish.
Top Tip - Many fishkeepers will not have the right water for these fish out of their tap. Instead they opt to use reverse osmosis (RO) water which can easily be manipulated to create the acidic conditions required and has the very low dissolved solids required for this species.
The region is truly tropical, so stick with temperatures in the 23-28°C (73-82°F) range. This is not a species that requires a cool winter period.
Related article: Is rainwater safer than tapwater?
Diet and Feeding
In the wild they spend their time picking off drifting zooplankton, small worms amongst the leaf litter and any terrestrial insects that fall into the water.
Replicate this in captivity to see your Betta albimarginata at their best. Offer frozen and live food regularly with the likes of mosquito larvae, Daphnia and Cyclops being great options.
They will accept prepared foods as well, especially when tank bred. Small granules, flakes and crisps are all appreciated, but choose those that have a high level of insect protein to mimic their natural diet.
Related article: How to feed your new Betta.
Breeding Betta albimarginata
When kept in favourable conditions and given a varied diet, pairs of white-seam Bettas will usually spawn readily. The courtship process can take a long time. The male and female will size each other up by stretching their fins while following each other around the aquarium.
Once receptive, the pair will embrace in a typical Betta fashion. As the eggs are released and fertilised, the male will collect them on his anal fin briefly for the female to pick up and transfer to the male's mouth. They will do this repeatedly until the female runs out of eggs.
The male will incubate the eggs in his mouth for around two weeks (temperature dependent). Once the fry are released by the male they will be free swimming and ready to feed. I had good success with raising the fry on vinegar eels, baby brine shrimp, freshwater copepods and then young Daphnia.
Top Tip- Raise your Betta fry in a mature botanical dominated aquarium. The naturally occurring microorganisms that grow in aquariums filled with leaf litter, like Indian almond leaves, will provide a supplemental food source.
The parents may predate on their fry, and in my experience the female is the most likely to do this. You can separate the adults from the fry once the male has released his offspring. You will know when he has released the clutch when he is out and searching for food again.
Alternatively, at around the 10 day mark, I have had success moving the male to a separate tank (with the same water). I transferred him using a beaker rather than a net to reduce stress.
The rearing tank for the fry should have a tight fitting lid or coverslide. This maintains a warm humid layer of air for the fry's developing labyrinth organ.