Sphaerichthys Osphromenoides (Chocolate Gourami)

IUCN Red List: Data Deficient (Threatened by ongoing peat-swamp habitat destruction)

Important note: Chocolate Gouramis are highly sensitive blackwater specialists recommended for experienced aquarists.

Sphaerichthys osphromenoides (“Chocolate Gourami”)

The Chocolate Gourami is a beautiful and unusual labyrinth fish native to the peat swamps and blackwater streams of Malaysia, Sumatra, and Borneo. Its deep, laterally compressed body features a rich chocolate-brown base color crossed by pale cream or golden vertical bands. Subtle red, blue, or cream edging may develop on the fins depending on the population and condition of the fish.

These gouramis naturally inhabit warm, extremely soft, acidic water beneath dense forest canopy. Their habitats contain abundant leaf litter, submerged branches, tannins, and humic substances. Peaceful but delicate, the Chocolate Gourami is best maintained in a mature, quiet blackwater aquarium with excellent water quality and carefully selected tankmates.

Size:
Adults typically reach 5–6 cm (approximately 2–2.4″) total length.

Water parameters:
Very soft, acidic water is strongly recommended.

pH 4.0–6.5
GH 0–4 °d
KH 0–1 °d
TDS preferably below 100 ppm

Provide leaf litter, botanicals, driftwood, floating plants, and subdued lighting. Filtration should be gentle, with minimal current and no accumulation of organic waste.

These fish are highly sensitive to ammonia, nitrite, elevated nitrate, and sudden changes in water chemistry. Add them only to a biologically mature aquarium.

Temperature:
25–29 °C (77–84 °F)

Maintain a warm, humid layer of air above the water by using a tightly fitted aquarium lid. This is especially important because Chocolate Gouramis possess a labyrinth organ and regularly breathe atmospheric air.

Food:
Primarily a micropredator that may initially refuse prepared foods.

Offer a varied diet including:

– Live or frozen daphnia
– Cyclops
– Baby brine shrimp
– Mosquito larvae
– Grindal worms and small bloodworms
– High-quality soft micro-granules

Live and frozen foods are particularly important during acclimation. Feed small portions once or twice daily and ensure shy individuals are not being outcompeted.

Tankmates:
A peaceful but timid species best kept in a group of approximately 4–6+ individuals, provided the aquarium offers sufficient space and cover.

Suitable tankmates include:

– Boraras
– Sundadanio
– Small peaceful rasboras
– Kuhli loaches
– Gentle Parosphromenus
– Small, peaceful blackwater fish

Avoid large, aggressive, highly active, or competitive feeders. Fin-nippers and territorial gouramis should also be avoided.

A species-focused aquarium is preferred, especially when acclimating newly acquired fish or attempting to breed them.

Breeding:
A mouthbrooding species with an unusual reproductive strategy.

Following courtship and spawning, approximately 20–40 eggs may be collected and incubated inside the male’s mouth for around two weeks. Older aquarium references frequently describe the female as the mouthbrooder, but current FishBase information identifies the male as the brooding parent. FishBase species summary

The brooding fish becomes reclusive and normally refuses food. It should not be chased, netted, or otherwise disturbed, as stress may cause the eggs to be swallowed or released prematurely.

Fully developed fry are released from the mouth and can be offered appropriately sized live foods, including microworms and newly hatched baby brine shrimp. Warm, extremely soft, acidic water and a quiet environment are important for successful reproduction.

Important note:
Chocolate Gouramis require careful acclimation and exceptionally stable conditions. Sudden increases in pH, hardness, temperature, or dissolved waste can result in rapid deterioration.

Avoid frequent rearrangement, excessive current, bright lighting, and boisterous tankmates. Observe each fish closely for feeding response, body condition, abnormal coloration, or isolation from the group.

This is not a general community fish. Chocolate Gouramis are best kept by experienced aquarists capable of providing mature, warm, extremely soft blackwater conditions and a consistent supply of small live or frozen foods.