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Samurai Gourami

Sphaerichthys vaillanti

The Reverse-Dimorphism Ghost (2.5 inches / 6 cm). The Samurai Gourami is an ultra-rare, ghostly, blade-shaped labyrinth fish from the heart of the Borneo jungle. It is incredibly famous among elite hobbyists for two reasons: its insane fragility, and the fact that the FEMALES are the brightly colored ones. When ready to breed, the female explodes into a mesmerizing zebra-striped 'Samurai Armor' pattern of deep blood-red and emerald green, while the male remains a dull, dusty brown leaf color. Keeping them alive is a master-class challenge.

Family
Osphronemidae
Origin
Borneo (Bacino del fiume Kapuas)
Origin
Extra-Amazon South AmericaSouth and Southeast Asia
Tank use
Used in 0 tanks

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Species challenges
Temperature

24 °C - 28 °C

pH

4 - 6

Water type

Freshwater

Tank level

Middle

Adult size

6 cm

Description

Geographic Origin and Biotope: An extraordinarily rare, incredibly delicate, and highly sought-after jewel endemic strictly to the Kapuas River basin in Kalimantan (Indonesian Borneo). Vaillant's Chocolate Gourami is an extreme, obligate "Blackwater" species: it clings to life in flooded peat-swamp forests, deeply shaded forest streams, and dense canopies where the water is utterly stagnant, practically devoid of minerals, and deeply stained the color of black tea by massive, rotting beds of fallen leaves and submerged roots.

Taxonomy and Morphology: A highly distinct and specialized anabantoid of the Osphronemidae family, completely lacking the roundness of standard gouramis. It possesses a slender, heavily compressed, torpedo-like body, culminating in an incredibly pronounced, sharp, pointed snout that distinctly resembles a seahorse profile—an evolutionary adaptation designed to probe deep into submerged leaf litter to extract micro-crustaceans. It notably lacks the long, sweeping tactile pelvic feelers signature to the *Trichogaster* genus. It is a diminutive dwarf, maxing out at a fragile 5-6 cm (2-2.5 inches) in captivity.

Social Behavior: Painfully shy, overwhelmingly timid, and peaceful to the point of lethal vulnerability. It is a gregarious, loose-shoaling species that heavily relies on group safety in the wild. Within a captive shoal, they establish extremely gentle, non-violent hierarchies. It is a pathologically slow, highly deliberate, hovering swimmer: it spends its entire day meticulously investigating dead leaves, and will instantly and frantically retreat into the darkest, deepest shadows if startled by a sudden shadow or loud footstep outside the tank.

Coloration and Sexual Dimorphism: One of the exceedingly rare anomalies in the vertebrate animal kingdom displaying reversed sexual dimorphism: the female is spectacularly, overwhelmingly more beautiful and heavily colored than the male. **Extreme Reverse Dimorphism:** When mature females enter breeding condition or display for dominance, their slender bodies violently erupt into a neon-painted canvas of alternating, stark vertical bands of deep rust-red and brilliant, metallic emerald-green or electric blue. Males, conversely, are tragically drab, uniformly dull, washed-out muddy brown or pale grey, featuring significantly fainter striping and a noticeably distended, swollen lower jaw (specifically evolved to hold eggs).

Care and observations

Tank Setup: It demands a maniacally controlled, dedicated "Blackwater" biotope (60-80 liters / 15-20 Gallons for a small shoal). The lighting MUST be dim, moody, and deeply spectral; bright reef lights will terrify them into permanent hiding. Water flow must equal absolute zero: mature, gentle sponge filters are the only option. The aquascape MUST be an impenetrable fortress of dark wood, Manila roots, and the substrate heavily carpeted in thick, overlapping layers of dried botanical leaves (Catappa/Almond, Oak, Alder cones) that will leach heavy humic acids to stain the water pitch dark. A tightly sealed glass canopy is critical for its fragile labyrinth lung.

Feeding and Diet: A hyper-specialized, exasperatingly picky micro-predator. Wild-caught specimens (which comprise almost all stock) will categorically, stubbornly refuse all dry, commercial flake or pellet foods, choosing to literally starve themselves to a skeletal death. The aquarist MUST source living daphnia, live baby brine shrimp (nauplii), microworms, and grindal worms to trigger their feeding reflex. Over months of supreme patience, they can sometimes be transitioned to frozen bloodworms. They must be fed tiny, frequent meals: their sharp snouts and weak jaws cannot process or swallow large chunks of meat.

Water Quality: The ultimate Achilles' heel of the species: it demands agonizing, surgically precise water chemistry or it will rapidly melt away. The water must be heavily heated (26-30°C / 79-86°F), but crucially, it must be almost completely devoid of dissolved minerals: GH must be 0-3, and the pH must be horrifyingly acidic, crashing between 4.5 and 5.5 (max 6.0). Creating this requires a dedicated Reverse Osmosis (RO) water system filtered heavily through pure active peat moss. The slightest trace of ammonia, or housing them in basic pH 7.5 tap water, instantly destroys their fragile slime coat immune system, guaranteeing a swift death.

Compatibility: A 100% uncompromising "Species-Only" tank requirement. This Gourami is so pathologically timid, slow, and delicate that it will be hopelessly outcompeted for food, bullied, or stressed into lethal organ failure if housed with even mildly dynamic fish (like Tetras, Guppies, or energetic Rasboras). It must NEVER have to compete for a meal. The only remotely acceptable tankmates are microscopic, peaceful Boraras (e.g., Chili Rasboras) or peaceful snails, living strictly within a supportive shoal of 6-8 of its own kind to provide it with the psychological courage to come out of the shadows.

Reproduction in Captivity: A breathtaking, fascinating paternal Mouthbrooder. Unlike standard gouramis that build bubble nests, in *S. vaillanti*, the stunning, brightly colored female aggressively courts the drab male. Following a gentle nuptial embrace near the dark tank floor, the female gathers the massive, very few eggs (10-40 total) and literally SPITS them directly into the waiting mouth of the male. The male immediately retreats into absolute darkness, refusing all food and starving himself completely while he incubates the eggs in his buccal cavity for 10-15 agonizing days. In captivity, if the brooding male is even slightly stressed by the owner peering in or flashing a light, he will panic and swallow all the eggs to survive.

Risks and Diseases: 1. Osmotic Collapse (Lethal Velvet/Oodinium): If dumped into standard, alkaline tap water (pH above 7.0), their protective slime coat burns off. They will be instantly decimated by an incurable outbreak of Velvet disease (gold dust parasite) or flesh-eating fungus within a week. 2. Terminal Starvation: Newly imported wild specimens are perpetually terrified and refuse food; they will waste away to literally skin-and-bones and die if live, wriggling food is not provided immediately. 3. Total loss of fry due to paternal panic.

Fish profile

Tank level
Middle
Adult size
6 cm
GH
0 dGH - 5 dGH
KH
n/a
TDS
n/a
Conductivity
n/a

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.