Licorice Gourami Care: The Ultimate Guide to Parosphromenus

Species Overview#

The licorice gourami (Parosphromenus deissneri) is one of the aquarium hobby's quiet obsessions. While the dwarf and pearl gouramis crowd the front glass at every chain store, this 1.5-inch peat-swamp specialist hides in shadow, shows its colors only during courtship, and demands water acidic enough to dissolve concrete. The reward for getting it right is a fish that flares iridescent red, blue, and turquoise in a head-down spawning display that almost no other freshwater species can match.

There are now more than 20 described Parosphromenus species, and P. deissneri is technically the type species of the genus, originally described from Bangka Island, Indonesia in 1859. In practice, much of what enters the trade as "licorice gourami" is actually one of the closely related complex members — P. linkei, P. bintan, or P. harveyi — but the care requirements are nearly identical across the genus. What follows applies to all of them.

Adult size

1.2-1.5 in (3-4 cm)

Lifespan

3-5 years

Min tank

5-10 gallons (per pair)

Temperament

Shy, mildly territorial

Difficulty

Expert

Diet

Micropredator (live foods)

Identifying Parosphromenus deissneri vs. other complexes#

Parosphromenus deissneri is a slender, torpedo-shaped fish with two parallel dark lateral stripes running from snout to caudal peduncle, separated by a band of cream or pale gold. At rest, both sexes look similar to a stretched-out chocolate gourami — drab, brownish, and easy to overlook. The genus is divided informally into "complexes" based on courtship coloration: the deissneri complex shows red and blue fin margins, while the parvulus complex tends toward turquoise and white.

Telling true deissneri from its lookalikes requires examining the male's flared dorsal and anal fin pattern under spawning conditions. Authentic P. deissneri males display a black submarginal band edged in iridescent blue with a thin red outer margin. If you are sourcing from a specialty importer, ask for collection locality data — Bangka Island fish are the nominal form. For most hobbyists, any properly conditioned Parosphromenus sold under this name will deliver the same care experience.

Natural habitat: Southeast Asian peat swamps#

In the wild, licorice gouramis live in the tea-stained peat swamp forests of Sumatra, Borneo, and the Malay Peninsula. These are not rivers in the conventional sense — they are slow seeps and shallow pools through fallen leaf litter, with so much dissolved tannin that the water looks like espresso. Recorded pH values from collection sites routinely fall between 3.5 and 5.5, with conductivity under 30 microsiemens and effectively zero general hardness.

The water moves so slowly that a current is nearly imperceptible, and dissolved oxygen is low — which is why Parosphromenus and other anabantoids evolved the labyrinth organ, an accessory air-breathing structure that lets them gulp atmospheric oxygen at the surface. Re-creating these conditions, not just approximating them, is the difference between a fish that survives and a fish that spawns.

Sexual dimorphism: Identifying vibrant males vs. cryptic females#

Outside of spawning condition, sexing licorice gouramis is genuinely difficult — both sexes are slim, brown, and lateral-striped. The reliable cue is the unpaired fins. Males develop elongated, pointed dorsal and anal fins with iridescent margins, and during courtship they flare these fins to display the species-specific color band.

Females remain consistently drab with rounded, shorter fins and never develop the iridescent fin margins. A gravid female may show a slightly fuller belly when ready to spawn, but the fin shape is the dependable indicator. If you are buying a "pair" from an LFS, insist on seeing both fish in good light — many pairs sold as such turn out to be two males or two females.

Water Parameters & Tank Requirements#

Get the water chemistry wrong and nothing else matters. Licorice gouramis will not eat, will not color up, and will not survive long in standard tap water, no matter how much driftwood you add. This is the single hardest thing about the species and the reason it remains a niche fish.

Achieving extreme soft water (pH 3.5-6.0, TDS < 50)#

You cannot reach these parameters from municipal tap water without help. The only practical route is reverse osmosis (RO) water — either a home unit (around $150-300) or jugs from a fish store that sells RO. Pure RO has a TDS of 0-5 and zero buffering, which is the blank canvas you need. Remineralize lightly with a single botanical-source: a small handful of Indian Almond Leaves and a thin layer of peat-derived substrate will drop the pH naturally to the 4.5-5.5 range over a week.

Avoid chemical pH-down products. They use phosphoric acid that crashes pH instantly, then rebounds when buffering returns, killing fish in the swing. Tannin-driven acidification is gentle, self-stabilizing, and matches the wild process. For a deep dive on RO setup, mineral additives, and tannin sourcing, see the Blackwater Chemistry 101 callout below.

The role of Indian Almond Leaves and botanical tannins#

Indian Almond Leaves (Terminalia catappa) are the workhorse botanical for Parosphromenus tanks. As they decompose over 4-8 weeks, they leach humic and fulvic acids that tint the water amber, lower pH, and bind heavy metals. Equally important, the biofilm that grows on submerged leaves is a primary food source for fry and a grazing surface for adults.

Layer the bottom with a mix of catappa leaves, oak leaves, alder cones, and a few pieces of malaysian driftwood. Rotate fresh leaves in every 3-4 weeks as old ones break down. The visible tannin stain is not just decoration — it indicates the humic substances actively buffering your pH and suppressing pathogens.

Low-flow filtration: Using sponge filters for bubble-nest safety#

A licorice gourami tank should be effectively still. The species evolved in seeps, and any current strong enough to move a leaf will disrupt courtship and destroy bubble nests. The only filter that belongs on this tank is a small air-driven sponge filter set to a slow trickle of bubbles.

Skip canister and HOB filters entirely. Their flow is wrong, their intakes will trap weak fish or fry, and their plastic media leaches buffering compounds. A single Hydro-Sponge II or ATI Hydro-Sponge driven at minimum air output provides plenty of biofiltration for a lightly stocked 10-gallon. Bear in mind that nitrifying bacteria are inhibited below pH 6, so heavy plant uptake (java moss, Cryptocoryne, floating frogbit) does most of the actual nitrogen processing in a true blackwater tank.

Diet & Feeding#

This is the second-hardest thing about the species and the reason most newcomers fail. Licorice gouramis are obligate live-food micropredators. They will not reliably take flake, pellet, or even most frozen foods in their first months in captivity, and a fish that refuses food for two weeks is generally a dead fish.

The challenge of "live food only" requirements#

In the wild, Parosphromenus hunt copepods, mosquito larvae, daphnia, and other microcrustaceans drifting through leaf litter. Their feeding response is triggered by movement, and a motionless flake or pellet simply does not register as food. Some specimens, after months of conditioning, will accept frozen cyclops or frozen baby brine shrimp — but plan your feeding strategy around the assumption that live cultures are mandatory.

Feed twice daily, small amounts. The fish should always be hunting something. A drift of live baby brine shrimp through a clump of moss is the classic delivery method.

Culturing baby brine shrimp (BBS) and microworms#

Baby brine shrimp (BBS) is the staple. A San Francisco Bay Brand hatchery dish or DIY two-liter bottle setup costs under $30 and produces enough BBS daily to feed several pairs. Hatch eggs in saltwater for 24-36 hours, then rinse and feed.

Backstop BBS with one or two other live cultures: microworms (Panagrellus redivivus) are dirt-cheap and self-sustaining, walter worms tolerate slightly cooler conditions, and grindal worms are larger and good for adults. If you have outdoor space, daphnia and seed shrimp cultures provide variety. Frozen cyclops and frozen daphnia are reasonable backup options once fish are settled, but neither reliably triggers a strong feeding response in newly imported stock.

Why they often refuse flakes and pellets#

Beyond the movement-trigger issue, prepared foods foul soft acidic water rapidly. Uneaten pellets sink, decompose, and contribute ammonia in a tank with limited nitrifying capacity (remember, nitrifiers struggle below pH 6). Even if a Parosphromenus could be persuaded to nibble dried food, the water-quality cost would be net-negative.

Some long-term keepers report success training captive-bred fry to accept Hikari Micro Pellets or crushed flake by mixing them into a stream of live BBS. This is a multi-month project and should be considered a bonus, not a primary feeding plan.

Tank Mates & Compatibility#

The honest answer is that licorice gouramis are best kept alone. Any tank mate competes for the live food they need, and most tank mates are bolder, faster, and more dominant. If you are committed to a community look, your options are narrow.

The case for a species-only "biotope" tank#

A 10 to 20-gallon species tank with one or two pairs of P. deissneri, dense leaf litter, dim lighting, and a handful of low-light plants is the gold-standard setup. Watching a confident, well-fed pair courting in their own dedicated tank is genuinely one of the most rewarding experiences in the hobby. Communities exist primarily to satisfy keeper aesthetics, not the fish's needs.

If you want to combine species, design the tank around the licorice gourami's needs and add slow, peaceful, surface-avoiding fish that can also tolerate pH 5.5 water.

Suitable nano-neighbors: Boraras rasboras and Kuhli loaches#

The short list of compatible species: chili rasboras, phoenix rasboras, exclamation point rasboras, and galaxy rasboras all stay under 1 inch, occupy the mid-water column, and tolerate blackwater chemistry. A small school of 6-8 of any single Boraras species adds movement without crowding the Parosphromenus.

Bottom-dwellers should be peaceful and slow. Kuhli loaches and pygmy corydoras work well in groups of 5+, and they actually help by stirring leaf litter to expose food. Sparkling gouramis (Trichopsis pumila) are sometimes recommended but can be surprisingly aggressive at the surface — proceed with caution.

Avoiding aggressive or fast-moving surface feeders#

Anything that hits the water surface fast is disqualified. That rules out bettas, guppies, danios, hatchetfish, and most other gouramis including honey, dwarf, and pearl gouramis. They will outcompete a Parosphromenus for food at every meal, and the slow-feeding licorice gourami will starve in plain sight. Tetras of any kind are similarly disqualified — too fast, too hungry, often nippy.

Breeding the Licorice Gourami#

Successfully breeding Parosphromenus in captivity is one of the genuine bragging rights in freshwater aquaria. Spawning happens in dedicated cave-style sites — typically the underside of a small clay pot, a halved coconut shell, or a film canister — and the male performs all parental care.

Cave spawning and "head-down" courtship displays#

When water parameters are correct (pH under 5, temp around 76F, TDS under 30) and the female is gravid, the male claims a small cave. He hangs vertically inside the cave entrance with his head pointed down, flaring his fins to display the iridescent red and blue margins. The female approaches, the male wraps her in a brief embrace, and 15-30 eggs drift up to stick to the cave ceiling.

This courtship can stretch over several days and is the only time the species shows full color. If your setup is right, the display alone is worth the effort even if no fry survive.

Paternal care and bubble nest maintenance#

Unlike most anabantoids, Parosphromenus males build a sparse bubble nest on the cave ceiling rather than the water surface, and they tend the eggs entirely from inside the cave. The male will fan the eggs continuously and retrieve any that fall, replacing them in the nest. Females should be removed once spawning is complete, as the male will defend the cave and the female can be harassed.

Eggs hatch in 2-3 days, and fry remain inside the cave clinging to the ceiling for another 5-7 days while absorbing yolk. The male continues to guard until fry are free-swimming, at which point he should also be removed.

Raising fry in acidic, infusoria-rich environments#

Licorice gourami fry are tiny — too small for newly hatched brine shrimp in their first week. They need infusoria, vinegar eels, or paramecium cultures as a starter food. After 7-10 days they can take BBS, and then growth proceeds steadily.

Keep the rearing tank as small and stable as possible. A 2-3 gallon plastic tub with the same blackwater parameters as the parent tank works well. Daily small water changes with pre-acidified RO are critical, since fry are even more sensitive to ammonia than adults.

Common Health Issues#

Most licorice gourami deaths are environmental, not pathogenic. Get the water and food right and the species is unexpectedly hardy. Get them wrong and the fish dies in days.

Sensitivity to nitrate spikes and "old tank syndrome"#

Despite their preference for tannin-rich, lightly buffered water, Parosphromenus are extremely sensitive to nitrate accumulation. The trap is "old tank syndrome" — a tank that runs for 6-12 months without water changes builds up nitrates and dissolved organics while the pH continues to drift down. The fish look fine, then start dying suddenly when a partial water change shocks them with rapidly different chemistry.

The fix is consistency: 10-15% RO water changes every 7-10 days, pre-mixed to match tank parameters within 0.2 pH units and 5 ppm TDS. Test nitrate weekly and target under 10 ppm.

Velvet and fungal infections in hard water#

When Parosphromenus are kept in inappropriate parameters — pH above 7, GH above 6 — the immune compromise shows up as velvet (Oodinium) or fungal patches on fins and gills. Velvet looks like fine gold dust under a flashlight beam and is fatal within days if untreated. Standard copper-based velvet treatments will also kill Parosphromenus; use Seachem ParaGuard or salt-free anti-parasitic protocols and address the underlying water chemistry immediately.

Fungal infections appear as cottony white tufts and almost always indicate either water above 80F, low oxygen, or pH chasing back toward neutral after a buffering crash. Fix the root cause first, then treat with methylene blue baths if needed.

Where to Buy & What to Look For#

Licorice gouramis almost never appear in chain stores. When they do, the stock is usually mislabeled (often as "chocolate gourami" or generic "Parosphromenus sp.") and frequently in poor condition. Plan to source from a specialty importer.

Sourcing from specialized LFS vs. generic chains#

Look for online sellers and dedicated aquatics shops that import directly from Southeast Asian collectors — Wet Spot Tropical Fish, Dan's Fish, The Wet Spot, and similar regional specialty stores. These sources typically offer collection locality data (essential for distinguishing deissneri from related complex members) and quarantine fish for 2-4 weeks before sale. Expect to pay $25-50 per fish, with breeding pairs sometimes reaching $100+.

Local fish stores worth supporting are independents that handle wild Asian softwater species regularly. If your LFS keeps Asian arowanas, wild bettas, or chocolate gouramis in proper blackwater displays, they are likely a good source for Parosphromenus. Build a relationship and ask to be notified when a shipment arrives.

Checking for "sunken belly" and active foraging#

The single best in-store health check is the belly profile from above. A healthy Parosphromenus has a slightly rounded ventral line. A starving fish has a visibly sunken or pinched belly behind the gills — and once a licorice gourami reaches this point, it rarely recovers. Pass on any fish with this look.

Watch for active foraging. Even a freshly imported Parosphromenus should investigate live BBS in the seller's tank. If the fish hangs motionless in a corner, ignores food, and shows clamped fins, do not buy it regardless of price. Also check for clear eyes, intact fins without erosion, and the absence of any fuzzy patches or gold dusting.

Quick-Reference Cheat Sheet#

A condensed setup guide for a single pair of licorice gouramis in a 10-gallon species tank:

• Tank size: 10 gallons (5 gallons absolute minimum for one pair)
• Water source: 100% RO water with light remineralization (Seachem Equilibrium, half dose)
• pH: 4.5-5.5, achieved with Indian Almond Leaves and peat substrate (no chemicals)
• TDS: 30-50 ppm
• Temperature: 76F, stable
• Filtration: One small air-driven sponge filter at minimum bubble output
• Substrate: Dark sand with a thick layer of catappa leaves, oak leaves, and alder cones
• Plants: Java moss, Cryptocoryne parva, floating frogbit (low-light tolerant only)
• Hardscape: Malaysian driftwood, 2-3 small clay caves or halved coconut shells
• Lighting: Dim, ideally with floating plants providing cover
• Stocking: 1 pair Parosphromenus deissneri, optionally 6-8 chili rasboras
• Diet: Live baby brine shrimp twice daily, supplemented with microworms and grindal worms
• Water changes: 10-15% weekly with pre-matched RO water (parameters within 0.2 pH)
• Nitrate target: Under 10 ppm

Get those fundamentals right and the licorice gourami stops being an "expert-only" curiosity and becomes a cooperative, courtship-displaying jewel of a fish. Get any single one of them wrong, and you will be replacing fish every two months. The species rewards patience and punishes shortcuts — which is exactly why dedicated keepers find it so satisfying to maintain.