Betta Albimarginata

Betta albimarginata is a tiny, striking gem from Kalimantan’s Sebuku River drainage in Borneo, prized for the pure white margins that trim its fins. Endemic to the forest streams of East Kalimantan, this species brings a natural, rainforest vibe to a dedicated home aquarium while rewarding observant keepers with subtle, shimmering colour and active behaviour. What makes this Betta unique - Distinctive white margined fins that stand out in shaded, dimly lit setups—a true focal point in a species-only display. - Compact size (25–30 mm) makes it ideal for pair or small-group displays in a 45 × 30 cm aquarium. - Naturally blackwater-adapted physiology: thrives in very soft, acidic conditions with minimal carbonate hardness, echoing its forest-stream origin. - Practical, sustainability-minded setup: you can maintain a fully-decorated tank or simplify by foregoing substrate; driftwood, roots, and leaf litter recreate its native microhabitat and support a thriving microbe-based feeding microcosm for fry. Ideal aquarium setup and care essentials - Tank and layout: A 45 × 30 cm base is perfect for a pair or small group. Create shady zones with driftwood, roots, and branches, and place clay plant pots or piping for additional cover. A light layer of leaf litter accelerates beneficial microbe growth and offers natural cover for shy individuals. - Substrate choice: A fully-decorated, substrate-free approach is common among breeders, but any setup that provides hiding spots and gentle zones of shade will suit this species well. - Lighting: Dim lighting is preferable to mirror its natural blackwater habitat and to keep coloration rich and eye-catching. - Floating and bottom-dwelling greens: Include plants that tolerate low light—Microsorum (Java fern), Taxiphyllum (Java moss), and Cryptocoryne spp.—as well as a few patches of floating plants to diffuse light and provide shade. - Water chemistry and filtration: Target soft water with very low carbonate hardness and low general hardness. RO water or a similarly soft source is often needed, with careful, controlled acidification if necessary to maintain pH around 4.0–6.5. Filtration should be gentle; an air-powered sponge filter with light turnover helps simulate the slow-flow streams these fish love. - Temperature: Maintain 23–28 °C to support steady metabolism and vibrant fins. - Tank maintenance: The species tends to benefit from leaf litter decomposition, which fuels microbe colonies that can serve as a secondary food source for fry. There’s no need to collect natural peat; stick to leaf litter and soft filtration to keep things clean and sustainable. Diet and feeding strategy - In the wild, Betta albimarginata preys on small insects, invertebrates, and zooplankton. In an aquarium, acceptances usually extend to small live or frozen foods once recognised as edible. - Practical feeding plan: offer Daphnia, Artemia, and bloodworm regularly to support colour development and condition. Include small, palatable dried foods to ensure a balanced diet, but avoid overfeeding to prevent obesity. - Feeding cadence: provide small portions multiple times a day rather than large meals, and adjust based on activity and body condition. Behavior, compatibility, and observation - Not recommended for standard community tanks due to its habitat needs and specific water chemistry requirements. This species shines best in a dedicated, species-focused setup that respects its soft, acidic water preferences. - Social dynamics: Keep as a pair or in a small group within a suitably planted, dimly lit tank that offers ample hiding spots. Ensure the environment is stable and free from aggressive tank mates that could disrupt feeding and territory. - Jumper reminder: Like other Betta species, Betta albimarginata enjoys access to the humid air layer above the water. Keep the tank well-covered or use a secure lid to prevent escapes. Who this fish is ideal for - Experienced hobbyists seeking a distinctive, small Betta with striking white-edged fins and a deep appreciation for blackwater-inspired setups. - Aquarists building a species-focused display that prioritises naturalistic décor, microbe-based nutrition for fry, and careful water chemistry management. - Enthusiasts aiming to recreate a Southeast Asian forest stream within a home aquarium—complete with driftwood, leaf litter, and dim, shaded lighting. Practical tips for success - Plan for soft, acidic water from the start and monitor pH, hardness, and temperature regularly to keep conditions stable. - Use gentle filtration and avoid strong currents that can stress these calmer Betta individuals. - Introduce live or frozen foods gradually and observe feeding responses to prevent overfeeding. - Arrange décor to create multiple microhabitats: shady spots, open swimming lanes, and sheltered corners to reduce stress and encourage natural behaviours. Betta albimarginata delivers a rare combination of tiny size, striking fin margins, and an authentic forest-stream aesthetic. With thoughtful tank design, careful water management, and a targeted diet, you can enjoy a captivating, low-maintenance display that celebrates this remarkable Southeast Asian jewel.