Licorice Gourami Care Guide

The licorice gourami is an expert-only blackwater nano specialist, even more demanding than the dwarf or honey gouramis. It is tiny, shy, a micropredator that usually refuses dry food, and locked to extreme soft acidic water; it is also a genuine conservation concern, assessed by the IUCN as Endangered.

Licorice Gourami at a glance

The sourced figures the welfare engine uses to judge Licorice Gourami — the parseable key facts.

Where it comes from

Parosphromenus deissneri belongs to the peat-swamp forests of South-East Asia. True deissneri is endemic to Bangka Island in Indonesia, while the wider deissneri group sold in trade ranges across the Malay Peninsula, Sumatra, Borneo, Bintan and Riau, always tied to lowland blackwater. The habitat is tea-coloured jungle swamp and slow streams under dense canopy, with leaf litter, submerged roots and dim light, increasingly surviving only in degraded remnants. The wild chemistry is the whole story of the fish: measured habitat temperature around 27 C, pH of 3.0-4.0, and conductivity of just 4-8 microsiemens per centimetre, meaning the water is essentially mineral-free. Read that and the care follows: extreme soft acidic blackwater is mandatory, built from RO or rainwater with peat, leaf litter and botanicals; a dim, heavily covered, mature tank with gentle flow; and warmth, though keepers often run it slightly cool for longevity. Like other anabantoids it is a facultative air-breather with a labyrinth organ.

Did you know?

• It lives in water about as acidic as swamp tea: wild habitats run pH 3.0-4.0 with conductivity of just 4-8 microsiemens per centimetre, essentially mineral-free tannin-stained blackwater.
• The type specimen was a single battered female, and we are still not certain the name is on the right fish; a neotype had to be designated in 1998 (Kottelat and Ng), and there is lingering doubt over which of two Bangka species deissneri belongs to.
• One name covers more than twenty fish: deissneri was the genus's only member for about a century, yet today there are roughly 20 to 25 recognised Parosphromenus species, with more expected, while much of the trade still labels them all deissneri.
• Dads do all the parenting, in a cave: the male alone guards eggs and fry through temporary pair bonds.
• It has its own conservation NGO: the volunteer Parosphromenus Project exists to census, captive-breed and conserve these fish as their peat-swamp forests are cleared.
• The epithet honours F. H. Deissner, a military health officer who shipped Bangka fishes to Bleeker.

Tank size — and why

A heavily planted nano of around 30-45 L (roughly 8-12 US gallons) suits a pair, and a small colony does better in about 20 gallons; our 10 gallon floor is a sensible, slightly generous figure. The reason is not swim volume, since this is a tiny, slow, sedentary fish. It is footprint for a dim, leaf-littered, cave-rich layout; chemical stability, because extreme-blackwater chemistry is unforgiving in tiny volumes; and room for males to hold small territories while females retreat in a colony. Prefer a long, low footprint over a tall tank; these are bottom-to-mid swamp fish.

As a guide, a 20-gallon tank comfortably suits about 2 Licorice Gourami as a single-species display, leaving room for tankmates.

See it to scale

Adult Licorice Gourami reach only about 4 cm (1.6 in) long — close to the size they are sold at, so what you see is roughly what you get. The catch is the group: a proper shoal still needs about a 10-gallon tank, around 51 cm long.

Adult size is sourced; tank length is approximate for a standard 10-gallon aquarium.

Water parameters in practice

This is why the fish is expert-only. It needs genuine soft acidic blackwater, not merely acidic-ish water: aim for pH about 4.0-5.5 (tolerated roughly 3.0-6.5), GH near zero (about 0-3 dGH), KH 1-2 dGH or lower, and conductivity well under 50-100 microsiemens, against a wild baseline of 4-8. Temperature is best at the cool end, about 23-26 C within a 22-28 C band, since cooler water favours longevity and sustained warmth above 27-28 C is best avoided. Keep ammonia and nitrite at zero in a fully mature tank and nitrate as low as possible, well below 25 mg/L. Note that FishBase lists pH 5.6-7.2, which is too high and conflicts with wild chemistry; do not use it as a target. RO or rainwater plus botanicals are mandatory, and tap water is unsuitable.

Diet & feeding

It is a micropredator on tiny aquatic invertebrates and, crucially, it largely refuses dry and prepared food. Seriously Fish notes that frozen foods are only sometimes accepted and that most dried products are normally refused, so feed a variety of small live and fine frozen foods: Artemia nauplii, Daphnia, Moina, microworm, grindal worm, mosquito larvae, copepods and flightless fruit flies. Give small portions once or twice a day, eaten within two or three minutes, since uneaten food fouls the small, sensitive tank fast. The practical implication for buyers is blunt: if you are not willing to culture or regularly source live foods, do not buy this fish, because it will slowly starve on flake. This is a primary cause of captive death.

Gear & setup

Set up a dim, heavily covered, biologically mature tank before adding fish. Use a dark substrate, leaf litter (catappa or oak), alder cones, bogwood, tight caves and dense or floating planting to diffuse the light; the caves and litter are spawning infrastructure, not decoration. Run gentle flow only, a sponge filter being ideal, and do frequent small water changes matched in chemistry, because the fish hates abrupt changes and chemicals. Keep the tank covered with a warm, humid air gap under the lid for the labyrinth organ, and do not fill to the brim.

Temperament & behaviour

Extremely peaceful and shy toward other species, but males are territorial toward each other, holding small territories and sparring, especially in breeding condition. So peaceful is true at the community level but not among males. Provide enough caves and cover that each male can hold a patch and females can retreat. In a bare, bright or under-decorated tank it hides constantly, stops displaying and stops eating; heavy cover, dim light and blackwater bring out its natural courtship and colour.

Group & social needs

Best kept as a bonded pair or a small colony in a species-only tank, with enough caves and cover for each male to hold a territory. Different Parosphromenus species must not be housed together: they compete and, where they are close relatives, can hybridise and destroy lineage purity. Females across the genus are hard to tell apart, so identification and pairing rely on a coloured-up male.

Compatible tank mates (preview)

The engine clears no fish into a clear top set with Licorice Gourami. It is not a species you can stock from a generic "peaceful community" list — shrimp, snails and small community fish are not safe defaults with it, so work from the temperament and tank-mate guidance in the sections above (and the full compatibility checker) rather than a quick shortlist.

This engine-cleared shortlist is Licorice Gourami's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

Breeding is intermediate-to-advanced, with the water chemistry being the real gate rather than the fish's willingness. It is a cave or leaf-litter spawner forming temporary pair bonds, and the male alone tends the eggs and brood, often in a small cave or among litter and sometimes building a rudimentary bubble nest. Males display in species-specific postures, with deissneri sometimes hanging near-vertical, head down, fins splayed. Trigger with a dedicated soft acidic blackwater spawning tank (pH about 4-6, GH and KH about 0-2 dGH, 22-26 C), dim light, caves and leaf litter, peace and stability. Eggs and milt are released in batches during repeated embraces; remove the female after spawning. Eggs hatch in roughly 24-36 hours and fry are free-swimming a few days later; first foods are infusoria, Paramecium and rotifers, then Artemia nauplii as they grow. Some sites call it one of the easiest gouramis to breed, but that is only true once the blackwater chemistry is dialled in; getting and holding that chemistry is the hard part.

Lifespan

Sources cluster at about 3-6 years. Conservative blackwater care sheets give 3-5 years, while one secondary source reaches about 6, and 3-4 years is a common real-world outcome under good care. A well-kept fish realistically lives roughly 3-5 years, with about 6 as a good-case ceiling and far shorter in unsuitable hard, alkaline, unstable, high-nitrate or dry-food-only tanks. No documented maximum age appears in the primary taxonomic sources. What shortens it: wrong water chemistry, nitrate and parameter swings, starvation on refused dry food, ammonia or nitrite from an immature tank, and stress from boisterous tankmates or bright open tanks.

Common mistakes

• Buying it for a community tank. It is not a community fish and needs a species-only blackwater tank; putting it with normal community fish and normal water is the classic fatal mistake.
• Keeping it in tap, neutral or hard water. Wild pH is 3-4 at around 5 microsiemens, so without RO or rainwater plus botanicals to reach soft acidic blackwater it declines and never breeds.
• Feeding only flake or pellets. It usually refuses dry food and needs live or fine frozen micro-foods; flake-only is slow starvation.
• Adding it to an immature or unstable tank. It is hypersensitive to ammonia, nitrite, nitrate and swings, so the tank must be biologically mature and changes small and matched.
• Assuming the deissneri on the label is correct. Most trade deissneri are other Parosphromenus species, so you may be mixing several species without knowing.
• Mixing different Parosphromenus species, which risks competition and hybridisation; keep one species per tank.
• Ignoring conservation and sourcing. Many Parosphromenus are threatened by peat-swamp destruction, so prioritise captive-bred fish and preserve lineage purity.

Signs of trouble

• Constant hiding and a refusal to display or court, usually a sign of wrong water, too little cover, or too much light.
• A thinning body and sunken belly, the classic look of slow starvation on refused dry food.
• Faded colour and lethargy, often the first stage of wrong-water decline.
• Clamped fins, rapid breathing or surface gasping, pointing to poor water quality or chemistry swings.
• White spots, velvet film or fungal patches, typically secondary to stress, chilling or wild-caught condition.

Is this fish right for you?

Don't buy this fish if you cannot provide a mature, dimly lit, heavily covered species-only blackwater tank with RO or rainwater-based soft acidic water (pH about 4-6, near-zero hardness), a reliable supply of live or fine frozen foods, and the patience for a shy, hiding, expert-level fish, or if you cannot verify responsible, ideally captive-bred sourcing. There are no selectively-bred colour morphs; the variety in the trade is different wild species sold under one name. Because the genus is being pushed toward extinction by peat-swamp clearance for palm oil, timber and tin, and deissneri itself is IUCN Endangered, the ethical choice is captive-bred stock from keepers who track geographic lineage, not freshly wild-caught fish of uncertain identity.

Bringing one home

Most trade fish are wild-caught and often arrive stressed, thin, parasitised or misidentified, so quarantine and condition on live foods before any breeding attempt. Acclimate slowly into mature, soft acidic water, since the species is acutely sensitive to ammonia, nitrite and sudden parameter or chemical shifts, and be aware that many medications are harsh in low-pH blackwater, making correct chemistry and live food the better preventatives.

Common questions

Is the licorice gourami good for beginners?

No, it is expert-only. The mandatory extreme soft acidic blackwater (pH around 4-5.5, near-zero hardness), the refusal of dry food, and the muddled identity of trade stock make it one of the harder nano fish to keep well.

What water parameters does a licorice gourami need?

Genuine blackwater: pH about 4.0-5.5, GH near zero, very low KH, conductivity well under 50-100 microsiemens, and a cool 23-26 C. Use RO or rainwater plus botanicals; ignore FishBase's pH 5.6-7.2, which conflicts with the wild chemistry.

Can licorice gouramis go in a community tank?

No. They are not recommended for the general community; keep them species-only. The risk runs both ways, since boisterous fish out-compete them and a community tank cannot be run at the pH 4-5 blackwater they need.

What do licorice gouramis eat?

Small live and fine frozen foods: brine shrimp nauplii, Daphnia, Moina, microworm, grindal worm and similar. They usually refuse dry flake and pellets, so live foods are effectively required to keep them from starving.

Is my fish really Parosphromenus deissneri?

Probably not. True deissneri is endemic to Bangka, and most fish sold as deissneri are other Parosphromenus species. Reliable identification needs a coloured-up mature male, so do not mix species you cannot verify.

Are licorice gouramis endangered?

Yes, deissneri is assessed by the IUCN as Endangered, and the wider genus is under heavy pressure from peat-swamp clearance for palm oil, timber and tin. Favour captive-bred stock and avoid contributing to wild collection.

Sources & confidence

Sources & confidence (1 species)

These back the Licorice Gourami figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Licorice Gourami Parosphromenus deissneri — Seriously Fish (seriouslyfish.com/species/parosphromenus-deissneri) medium confidence

Care-guide sources (6)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• Seriously Fish — Parosphromenus deissneri (Deissner's Liquorice Gourami)
• FishBase — Parosphromenus deissneri
• The Parosphromenus Project — The genus / Discovery
• The Parosphromenus Project — Threats
• Wikipedia — Licorice gourami (Parosphromenus deissneri)
• aqua-fish.net — Licorice Gourami (Parosphromenus) Care

More on Licorice Gourami

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →