Samurai Gourami

Sphaerichthys vaillanti is closely related to the Chocolate Gourami and shares its requirement for extreme blackwater conditions, but it is considered by many to be even more visually striking. Males display an extraordinary pattern of metallic, iridescent scales — green, gold, and blue reflections on a dark background — creating an effect reminiscent of polished samurai armor. Females are more subdued with the typical chocolate-brown and pale banding of the Sphaerichthys genus.

Endemically native to the peat swamp forests of Borneo, this species inhabits the most extreme blackwater environments: pH below 4, near-zero hardness, extremely tannin-rich water. These conditions are very challenging to replicate in the home aquarium and require RO water, heavy peat or botanicals use, and vigilant maintenance.

Like Sphaerichthys osphromenoides, the Samurai Gourami is a mouthbrooder, but it is the female who holds the brood — making it one of the few maternal mouthbrooding labyrinth fish. It is peaceful and best suited to a species-specific setup or a tank housing only other extreme blackwater species. Its rarity, beauty, and behavioral complexity make it a prized species among advanced freshwater aquarists. The Samurai Gourami's female mouthbrooding behavior is particularly unusual because maternal mouthbrooding is rare among labyrinth fish — the vast majority are paternal mouthbrooders or bubble-nest builders. This reversal of typical labyrinth reproductive roles adds a layer of fascination for aquarists interested in fish reproductive biology and makes successful breeding of this species all the more memorable.

Tank Setup A dedicated blackwater biotope is mandatory. Use fine dark substrate, abundant botanical litter (Indian almond leaves, dried seed pods, alder cones), driftwood, and very dim lighting — ideally only from indirect ambient light or a very weak LED. Filter through peat or a large quantity of Indian almond leaves. Minimal flow. No bright decorations or artificial items.

Water Parameters Extreme acidic blackwater: pH 4.0–6.5, GH near zero, TDS 20–60 ppm. Use RO water conditioned with peat extract and botanicals. Temperature 24–28°C. Small, frequent water changes (10–15% twice weekly) using perfectly matched water are better than large, sudden changes.

Feeding Offer tiny live and frozen foods: baby brine shrimp, daphnia, micro worms, vinegar eels, and small Grindal worms. May accept micro pellets over time. Feed small amounts twice daily. Live food significantly improves condition and breeding success.

Tankmates Species-only tank strongly recommended. Alternatively, pair with Boraras brigittae, Sundadanio axelrodi, or wild-type blackwater Betta species from Borneo that share identical requirements.

Female Mouthbrooding If breeding occurs, the female holds the brood — unusually for labyrinth fish. Remove the male after spawning. Do not disturb the female during the brooding period of 10–14 days.

Disease and Stress Extremely sensitive to incorrect water conditions, which rapidly lead to bacterial and parasitic infections. Never compromise on water chemistry. Avoid all copper-based medications.

Availability Rare in the hobby. Source from reputable specialist breeders rather than wild-caught imports when possible.

Long-term Notes Samurai Gouramis in appropriate conditions reward patient keepers with some of the most beautiful coloration achievable in a freshwater aquarium. Maintaining perfect blackwater parameters consistently over the species' 5-year lifespan requires genuine commitment but produces extraordinary results. Successful breeding events — with the female holding a brood — are among the most memorable experiences in the freshwater hobby. Female mouthbrooding behavior, if observed, should be protected by removing the male to a separate vessel immediately after spawning so the female is not harassed during the 10–14 day brooding period.