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Fire Red Licorice Gourami Care Guide – Tank Setup, Feeding and Breeding

ByTankora

Quick summary

The Fire Red Licorice Gourami is an advanced-level fish that needs extreme, soft, acidic blackwater conditions and live foods to thrive, making it unsuitable for beginners or standard community tanks. If you can commit to a dedicated species tank with RO water and a steady supply of live foods, it offers spectacular breeding colours and a rewarding, conservation-worthy challenge.

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In this guide:

Introduction

The Fire Red Licorice Gourami (Parosphromenus sumatranus) is one of the most striking and sought-after members of the genus Parosphromenus, a group of diminutive labyrinth fishes prized by dedicated hobbyists for their extraordinary courtship colours and fascinating breeding behaviour. Native to the peat swamp forests of Sumatra, Indonesia, this species demands specialist care and water conditions that closely replicate its natural blackwater habitat. It is not a fish for beginners, nor for community aquariums in the conventional sense, but for those willing to meet its exacting requirements, P. sumatranus offers a profoundly rewarding fishkeeping experience.

One of the most important points to understand before acquiring this species is the issue of misidentification. In the aquarium trade, P. sumatranus is frequently sold under the name of its close relative, Parosphromenus deissneri, and vice versa. The two species share overlapping ranges in parts of Sumatra and bear a superficial resemblance, particularly when not in breeding dress. Prospective keepers should source their fish from specialist breeders or reputable importers who can confirm the species identity, ideally with locality data. The Parosphromenus Project, an international conservation initiative, is an excellent resource for identification assistance and responsible keeping practices.

With an IUCN conservation status of Near Threatened, P. sumatranus faces serious pressure from habitat destruction in the wild, principally through peat swamp drainage for palm oil plantations and pulpwood forestry. Captive breeding is therefore not merely an interesting challenge but a genuine conservation contribution. Every hobbyist who successfully breeds this species helps maintain a genetic reservoir outside its increasingly imperilled native range.

Quick Stats

Scientific name Parosphromenus sumatranus
Common names Fire Red Licorice Gourami, Sumatran Licorice Gourami
Family Osphronemidae
Origin Sumatra, Indonesia (peat swamp forests)
Adult size 3 – 4 cm
Lifespan 3 – 5 years
Difficulty Advanced
Breeding difficulty Difficult
Temperature 22 – 28 °C
pH range 3.5 – 6.0
General hardness (GH) 0 – 4 dGH
Carbonate hardness (KH) 0 – 2 dKH
Minimum tank size 30 litres
Conservation status Near Threatened (IUCN)

Appearance

Outside of breeding display, P. sumatranus is an unassuming fish. Both sexes exhibit a base colouration of light brown to greyish-tan, overlaid with two prominent dark lateral bands that run from the snout through the eye and along the flanks. A third, less distinct band may be visible along the dorsal ridge. The overall impression is of a slender, somewhat cylindrical fish with subtle beauty – easily overlooked in a dealer’s tank, which is one reason the species is so often confused with congeners.

The transformation when a male enters breeding dress is, however, nothing short of spectacular. The unpaired fins – dorsal, anal, and caudal – expand dramatically and blaze with vivid colour. In P. sumatranus, the anal and caudal fins display bold bands of iridescent turquoise-blue and deep, fiery red, edged with fine white or pale blue margins. The dorsal fin mirrors this patterning. The body darkens considerably, intensifying the contrast with the luminous finnage. It is this display that gives the species its common name, Fire Red Licorice Gourami, and it is among the most visually arresting sights in the freshwater hobby.

Females are smaller and less intensely coloured, retaining the brownish base tones with the lateral banding. Their fins are shorter and rounder, lacking the elongated filaments seen in mature males. When receptive to spawning, females may develop a slightly warmer hue and show a subtle golden or cream tinge to their ventral region, but they never approach the dramatic colouration of displaying males.

Distinguishing P. sumatranus from P. deissneri requires careful observation of the fin patterning in displaying males. P. sumatranus typically shows a broader red band in the anal fin relative to the blue portion, and the caudal fin shape tends to be more rounded compared to the slightly more lanceolate form of P. deissneri. However, these differences can be subtle and are subject to individual and population-level variation, reinforcing the importance of sourcing fish with reliable provenance.

Natural Habitat

Parosphromenus sumatranus is endemic to the peat swamp forests of Sumatra, Indonesia. These habitats are characterised by waterlogged terrain where thick layers of decomposing organic matter – primarily fallen leaves, branches, and other plant debris – create a deep peat substrate. The water that percolates through this peat is stained a dark amber to almost opaque brown colour by dissolved tannins and humic acids, producing the classic blackwater conditions for which the genus is renowned.

The water in these habitats is extremely soft and acidic, often registering a pH between 3.5 and 5.0, with negligible mineral content. General hardness and carbonate hardness are typically unmeasurable by standard aquarium test kits. This is a crucial point: P. sumatranus has evolved over millennia in water that most freshwater aquarium fish would find utterly inhospitable. Attempting to keep this species in standard tap water, even if softened to moderate levels, will result in chronic stress, disease susceptibility, and failure to breed.

The peat swamps where P. sumatranus is found are typically shallow, slow-moving or still bodies of water – forest streams, drainage channels, and flooded depressions within the swamp forest. Light levels are low, filtered through dense canopy cover and further attenuated by the deeply tannin-stained water. Aquatic vegetation is sparse, but the substrate and margins are littered with leaf litter, submerged root tangles, and fallen wood, providing abundant cover and microbial grazing surfaces. Dissolved oxygen levels are low, which is precisely why the labyrinth organ – a specialised respiratory structure shared by all members of the suborder Anabantoidei – is so critical to the species’ survival.

Tragically, Sumatran peat swamp forests are among the most threatened ecosystems on earth. Large-scale conversion to oil palm plantations, pulpwood concessions, and associated drainage and burning have destroyed vast areas of this habitat. The IUCN listing of Near Threatened reflects these ongoing pressures, and some local populations may already be functionally extinct. This ecological context should inform every aspect of how hobbyists approach the keeping of P. sumatranus.

Tank Size and Setup

A single pair or a small group of three to four P. sumatranus can be housed in a tank as small as 30 litres, provided it is set up specifically for the species. Larger tanks of 45 to 60 litres offer more flexibility for maintaining stable water parameters and housing a small breeding colony. Regardless of tank size, the aquascape should prioritise cover, low light, and the creation of a dark, tannin-rich environment that mimics peat swamp conditions.

The substrate can be a thin layer of fine, inert sand or bare-bottom. Some keepers prefer bare-bottom tanks for ease of maintenance and to monitor feeding, while others use a scattering of peat fibre or coir over sand. Avoid any calcareous substrates or decorations, as these will buffer the water towards alkalinity and raise hardness – exactly the opposite of what is required.

The single most important aspect of the aquascape is the provision of abundant leaf litter. Indian almond leaves (Terminalia catappa), oak leaves, beech leaves, or other appropriate dried leaves should be added generously to the tank. These serve multiple purposes: they release tannins and humic acids that naturally acidify and stain the water; they provide cover and territorial boundaries; they support the growth of biofilms and microfauna (infusoria, rotifers, and small worms) that supplement the diet; and they create a naturalistic environment that reduces stress. A layer of leaves several centimetres deep on the tank floor is ideal.

Driftwood and small pieces of bogwood should be included, both for their tannin-releasing properties and to provide additional structure. Small clay or ceramic caves, halved coconut shells, or sections of small-diameter PVC pipe can serve as spawning sites, though many breeders find that P. sumatranus shows a strong preference for narrow, enclosed cavities – film canisters, small glass tubes, or commercially available ceramic caves designed for dwarf cichlid or Betta breeding are all suitable.

Lighting should be subdued. P. sumatranus is naturally found in very low-light environments, and bright illumination causes visible stress and colour loss. Floating plants such as Salvinia, Riccia, or water lettuce (Pistia stratiotes) help diffuse light and contribute to the blackwater aesthetic. Rooted plants are not essential and may struggle in the very acidic conditions, though species such as Cryptocoryne and certain mosses (Java moss, Christmas moss) can tolerate the parameters if given sufficient time to acclimatise.

A tight-fitting lid or cover glass is essential. As labyrinth fish, P. sumatranus must access atmospheric air at the surface. The air above the water should be warm and humid; a cold, dry air gap can damage the labyrinth organ over time.

Water Parameters

Parosphromenus sumatranus requires soft, acidic blackwater conditions that closely replicate its peat swamp habitat. This is non-negotiable for long-term health and any prospect of breeding. Standard community aquarium water is entirely unsuitable. Keepers must be prepared to use reverse osmosis (RO) water or demineralised water as the basis for their tank, remineralised only minimally if at all.

The target pH should be between 4.0 and 5.5 for general maintenance, with values as low as 3.5 tolerated and even preferred during breeding. Achieving and maintaining such low pH levels requires the virtual elimination of carbonate buffering capacity. Water should have a KH of 0 to 1 dKH and a GH of 0 to 4 dGH – the lower end of these ranges is preferable. Total dissolved solids (TDS) should ideally be below 50 ppm.

Tannins from leaf litter, driftwood, and peat extract or alder cones are the primary means of acidifying and conditioning the water. Some keepers also use commercially available blackwater extracts or humic acid supplements. It is important not to use pH-lowering chemicals designed for general aquarium use, as these can cause unstable swings and may contain compounds harmful to sensitive species.

Temperature 22 – 28 °C
pH 3.5 – 6.0
General hardness (GH) 0 – 4 dGH
Carbonate hardness (KH) 0 – 2 dKH
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate Below 10 ppm

It is worth noting that at very low pH values (below 4.5), the nitrogen cycle operates less efficiently, as the bacteria responsible for converting ammonia to nitrite and nitrite to nitrate are inhibited by extreme acidity. In practice, this means that the very low bioload of a small Parosphromenus tank, combined with heavy leaf litter and minimal feeding, generally prevents dangerous ammonia or nitrite accumulation. Nonetheless, regular testing with reliable kits rated for low-pH use is essential, particularly during the first few months of a new setup.

Filtration and Equipment

Filtration for a P. sumatranus tank must be gentle. These are fish of still or near-still waters, and strong currents cause stress, exhaust the fish, and can physically damage delicate fin extensions. A small air-driven sponge filter is the ideal choice. It provides biological filtration, gentle water movement, and surface agitation without creating problematic flow. The sponge also serves as a grazing surface for biofilm and microfauna.

If using a hang-on-back or small internal filter, ensure the flow rate is adjustable and set to the minimum. Spray bars or baffles can help disperse flow further. Under no circumstances should the tank have a noticeable current – if leaves on the surface are visibly pushed around, the flow is too strong.

Avoid filtration media that alter water chemistry. Activated carbon, for example, will strip tannins from the water, counteracting the blackwater conditions the keeper is trying to establish. Chemical filtration media are generally unnecessary and counterproductive. The filter should contain only sponge or ceramic biological media.

A heater rated for the tank size is necessary in most climates. An adjustable thermostat heater set to 24 – 26 °C is a good baseline; temperatures at the lower end of the range (22 – 24 °C) can be used to simulate a cooler season, while slightly warmer temperatures (26 – 28 °C) may encourage breeding activity. A reliable thermometer should be used to monitor temperature independently of the heater’s thermostat.

As mentioned, a tight-fitting lid is essential to maintain a warm, humid air layer above the water surface. Some keepers use cling film or glass cut to size if a proper aquarium lid is not available. Ensure there remains a small gap for air exchange, but prevent cold draughts from reaching the water surface.

Lighting should be minimal. A low-wattage LED on a timer, set for no more than eight hours per day, is sufficient. Many successful Parosphromenus keepers rely primarily on ambient room light or very dim aquarium lighting. The deep tannin staining of the water will further reduce light penetration, creating the dim, twilight environment in which these fish are most comfortable and display most naturally.

Diet and Feeding

Parosphromenus sumatranus is a micro-predator that overwhelmingly prefers live foods. In the wild, its diet consists of tiny invertebrates – insect larvae, copepods, cladocerans, and other zooplankton – gleaned from leaf litter and biofilm surfaces. Replicating this diet in captivity is one of the more challenging aspects of keeping the species, and it is a primary reason for its Advanced difficulty rating.

The most reliable staple foods in captivity are live baby brine shrimp (Artemia nauplii), Grindal worms, micro worms, Walter worms, banana worms, and Daphnia. Vinegar eels can also be used, particularly for conditioning breeding pairs or feeding newly free-swimming fry. Culturing one or more of these live foods at home is strongly recommended – indeed, it is practically essential for long-term success with the species.

Some individuals can be trained to accept frozen foods such as frozen baby brine shrimp, frozen Daphnia, or frozen Cyclops. However, many P. sumatranus will refuse frozen foods entirely, and others will accept them inconsistently. Freeze-dried and flake foods are almost universally ignored and should not be relied upon.

Feed small amounts once or twice daily. P. sumatranus has a tiny stomach and a correspondingly small appetite. Overfeeding is a common mistake, leading to water quality deterioration in these small, lightly filtered tanks. Observe the fish during feeding and remove any uneaten food after 15 to 20 minutes. The biofilm and microfauna sustained by the leaf litter in the tank will provide supplementary grazing between feedings.

Behaviour and Temperament

P. sumatranus is a shy, retiring species that spends much of its time hovering among leaf litter, driftwood, and other cover. It is not an active swimmer in the mould of danios or tetras; instead, it moves deliberately and methodically through its environment, pausing frequently to investigate surfaces for food or to survey its territory. This understated behaviour is part of the species’ charm and can be deeply absorbing to observe in a well-set-up species tank.

Males are mildly territorial, particularly when in breeding condition. They will claim a small cave or sheltered area and display to females and rival males by flaring their fins and intensifying their colouration. These displays are largely ritualistic and rarely result in physical damage. In tanks with sufficient cover and multiple potential spawning sites, several males can coexist peacefully.

Females are generally peaceful and unobtrusive. They may approach a displaying male’s territory to assess his suitability as a mate and will either enter the cave to spawn or move away if unimpressed. Outside of breeding activity, both sexes are tolerant of one another and can be kept in small groups.

P. sumatranus is easily stressed by boisterous, fast-moving, or aggressive tank mates. Even moderately active species can intimidate these tiny fish into permanent hiding, leading to chronic stress, refusal to feed, and eventual decline. For this reason, a species-only setup is strongly recommended and is the approach most likely to yield natural behaviour and breeding success.

Tank Mates

In most cases, the best tank mate for P. sumatranus is another P. sumatranus. Species-only tanks allow the keeper to maintain the extreme blackwater conditions the fish requires without compromise, and they eliminate the risk of competition, predation, or intimidation from other species. That said, a few very small, peaceful species that share similar water parameter requirements can coexist with P. sumatranus in sufficiently spacious and well-structured tanks. Any tank mate must tolerate very soft, acidic water with pH values below 5.0.

Good tank mates

Fish to avoid

Breeding

Breeding P. sumatranus is a challenging but deeply rewarding endeavour and one of significant conservation value given the species’ Near Threatened status. These are cave-spawning bubblenest builders, with the male constructing a small, fragile bubblenest inside a confined cavity and then courting a female to deposit eggs within it.

To condition a pair for breeding, ensure the water parameters are at their most extreme – pH 4.0 to 5.0, negligible hardness, and a temperature of 26 to 28 °C. Feed heavily with live foods, particularly baby brine shrimp and Grindal worms, for two to three weeks prior to the expected spawning attempt. Provide multiple small caves or enclosed cavities; film canisters, small ceramic tubes, or commercially available breeding caves positioned horizontally on the substrate work well.

A male in breeding condition will claim a cave and begin constructing a bubblenest on the inner ceiling. He will then display at the cave entrance, flaring his fins in full breeding dress to attract a passing female. If the female is receptive, she will enter the cave, and the pair will engage in a spawning embrace typical of osphronemids – the male wrapping his body around the female to fertilise the eggs as she releases them. Each embrace produces only a few eggs, and the entire clutch is typically small, ranging from 10 to 40 eggs.

After spawning, the male assumes sole responsibility for egg care. He tends the bubblenest, replacing burst bubbles, fanning the eggs, and removing any that become fungused. The female should be removed or allowed to leave the breeding area, as the male may become defensive. The eggs hatch in approximately 24 to 48 hours, and the fry remain attached to the bubblenest, absorbing their yolk sacs for a further two to three days before becoming free-swimming.

Raising the fry is the most difficult phase. Newly free-swimming P. sumatranus fry are extremely small and require infusoria, paramecium cultures, or vinegar eels as their first food. After one to two weeks, they can graduate to freshly hatched baby brine shrimp and micro worms. Growth is slow, and the fry are sensitive to water quality fluctuations. Partial water changes should be performed carefully, using water matched precisely to the tank’s parameters. Some breeders raise fry in the parent tank among dense leaf litter, relying on naturally occurring microfauna to supplement feeding; others transfer fry to a dedicated rearing container for closer monitoring.

Common Diseases

P. sumatranus is not particularly prone to specific diseases, but its requirement for extreme water conditions means that any deviation from ideal parameters can quickly lead to health problems. The most common issues are stress-related rather than caused by specific pathogens.

Velvet disease (Oodinium) is perhaps the most frequently encountered illness in Parosphromenus species. It manifests as a fine, gold or rust-coloured dusting on the body and fins, often accompanied by lethargy, clamped fins, and rapid gill movement. Velvet thrives in warm water and can spread rapidly in a small tank. Treatment with proprietary Oodinium medications can be effective, but dosing must be cautious, as these fish are sensitive to many chemical treatments. Raising the temperature slightly and dimming the lights (Oodinium is photosynthetic) can help in mild cases.

Bacterial infections, including fin rot, can occur when water quality deteriorates. In the very low pH conditions required by P. sumatranus, bacterial pathogens are naturally suppressed to some degree by the acidity and the antimicrobial properties of tannins. However, a sudden rise in pH or accumulation of organic waste can shift conditions in favour of pathogenic bacteria. Maintaining consistent water chemistry and performing regular small water changes with properly conditioned water are the best preventive measures.

Ich (white spot disease, Ichthyophthirius multifiliis) is less common in very acidic water but can occur, particularly if fish are introduced from holding systems with different water chemistry. Gradual acclimatisation of new arrivals is essential to reduce thermal and osmotic shock, which can trigger ich outbreaks.

Internal parasites may be present in wild-caught specimens. Quarantine all new arrivals in a separate tank with matching water parameters for a minimum of two to four weeks before introducing them to an established colony. Observe closely for signs of weight loss, bloating, or abnormal faeces.

Prevention is always preferable to treatment in Parosphromenus keeping. Stable water chemistry, appropriate diet, minimal stress, and scrupulous hygiene are the cornerstones of disease prevention. When treatment is necessary, use medications at reduced doses and monitor the fish closely for adverse reactions.

FAQs

How can I tell P. sumatranus apart from P. deissneri?

Reliable identification requires observing males in full breeding display. P. sumatranus typically shows a broader red band in the anal fin and a more rounded caudal fin compared to the slightly more elongated, lanceolate caudal of P. deissneri. Locality data from the supplier is extremely helpful – if the fish were collected from or bred from stock originating in specific regions of Sumatra, this can narrow identification considerably. The Parosphromenus Project maintains detailed photographic references and can assist with identification queries.

Can I keep P. sumatranus in a standard community aquarium?

No. The extreme blackwater conditions required by this species – pH below 5.0, negligible hardness, and very low TDS – are incompatible with the needs of almost all common community fish. Furthermore, P. sumatranus is shy and easily outcompeted for food by more assertive species. A dedicated species tank is strongly recommended for successful long-term keeping.

Will P. sumatranus accept dry or prepared foods?

In the vast majority of cases, no. P. sumatranus shows a very strong preference for live foods and will often refuse frozen, freeze-dried, and flake foods entirely. Keepers should be prepared to culture live foods such as baby brine shrimp, Grindal worms, micro worms, and Daphnia at home. Some individuals may eventually accept high-quality frozen baby brine shrimp or Cyclops, but this should not be assumed at the time of purchase.

How do I achieve and maintain such a low pH?

The key is to start with RO or demineralised water, which has no buffering capacity. Generous additions of Indian almond leaves, driftwood, peat extract, and alder cones will release tannins and humic acids that naturally drive the pH down. Avoid any substrates or decorations that contain calcium carbonate. Do not use chemical pH adjusters, as these can cause dangerous instability. In a well-established blackwater tank with heavy leaf litter and minimal mineral content, a pH of 4.0 to 5.0 can be maintained with relatively little intervention.

Is breeding P. sumatranus important for conservation?

Yes, very much so. P. sumatranus is listed as Near Threatened by the IUCN, and its peat swamp forest habitat in Sumatra is being destroyed at an alarming rate. Captive breeding by dedicated hobbyists helps maintain genetically viable populations outside the wild and reduces demand for wild-caught specimens. The Parosphromenus Project coordinates international breeding efforts and maintains studbook-like records for several species in the genus. Participation in such programmes is highly encouraged.

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