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Frail Gourami Care Guide – Tank Setup, Feeding and Breeding

ByTankora

Quick summary

The Frail Gourami is a shy, difficult species best suited to experienced aquarists who can maintain soft, acidic water and provide a diet of live and frozen foods, so it’s not recommended for beginners. It also requires a densely planted, low-light tank and careful tank mate selection, making it a poor first fish compared to hardier gouramis like the Honey or Pearl Gourami.

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In this guide:

Introduction

The Frail Gourami (Ctenops nobilis) is one of the most enigmatic and seldom-seen labyrinth fish available in the freshwater aquarium hobby. As the sole representative of the genus Ctenops, this monotypic species occupies a unique taxonomic position within the family Osphronemidae. Native to parts of northeastern India, Bangladesh, and Myanmar, it inhabits slow-moving waterways, floodplain marshes, and densely vegetated ditches – habitats that are themselves increasingly under pressure from human development and agricultural encroachment.

Unlike its more popular relatives such as the Dwarf Gourami or the Pearl Gourami, the Frail Gourami has never achieved mainstream popularity. This is partly due to its subdued colouration compared to many commercially bred gouramis, partly due to the genuine difficulty of sourcing healthy specimens, and partly due to its somewhat exacting care requirements. The common name “Frail” refers not to any inherent weakness in constitution but rather to the species’ slender, elongated body shape, which gives it a delicate appearance quite distinct from the deep-bodied profile of most gouramis familiar to hobbyists.

For the experienced aquarist seeking something genuinely different, the Frail Gourami offers a rewarding challenge. Its behaviour is fascinating – it is a mouthbrooder, which is unusual among anabantoids – and its subtle beauty becomes increasingly apparent the longer one keeps it. This guide provides comprehensive care information to help you maintain this uncommon species successfully in the home aquarium.

Quick Stats

Scientific name Ctenops nobilis
Common names Frail Gourami, Noble Gourami, Indian Frail Gourami
Family Osphronemidae
Origin Northeastern India (Assam, West Bengal, Meghalaya), Bangladesh, Myanmar
Adult size 8-10 cm (3-4 inches)
Lifespan 4-6 years
Difficulty Difficult
Breeding difficulty Advanced
Temperature 20-26 °C
pH range 6.0-7.5
General hardness (GH) 2-10 dGH
Carbonate hardness (KH) 2-6 dKH
Minimum tank size 75 litres
Conservation status Least Concern (IUCN)

Appearance

The Frail Gourami possesses an elongated, laterally compressed body that sets it apart from the rounder, deeper-bodied profile typical of many popular gourami species. The overall body shape is somewhat torpedo-like, tapering to a pointed snout that gives the fish a rather elegant, streamlined appearance. Adults typically reach 8 to 10 centimetres in total length, with males tending to be slightly slimmer and more intensely coloured than females.

The base body colour is a warm olive-brown to golden-brown, overlaid with a pattern of darker horizontal bands or rows of spots that run along the flanks. These markings can appear somewhat variable in intensity depending on the fish’s mood, health, and environment. When in prime condition and feeling secure, the colours deepen noticeably, and a subtle iridescent sheen – often bluish or greenish – becomes visible along the scales, particularly under oblique lighting. The fins are largely transparent to light brown, often with fine spotting or barring. The ventral (pelvic) fins are modified into the characteristic thread-like feelers seen in many anabantoid species, though in Ctenops nobilis these are relatively understated compared to those of some other gouramis.

The head is proportionally small with a distinctly pointed, slightly upturned mouth – an adaptation that hints at its surface-feeding tendencies and predatory nature towards small invertebrates. The eyes are moderately large and expressive, contributing to the alert, intelligent demeanour that keepers often remark upon. A dark lateral stripe, sometimes broken into a series of blotches, typically runs from the snout through the eye to the caudal peduncle, and this can intensify dramatically during social interactions or when the fish is stressed.

Sexual dimorphism is present but subtle. Males tend to display slightly more vivid colouration, particularly during breeding condition, and may develop marginally more pointed dorsal and anal fin extensions. Females are generally a touch fuller in the body when mature and carrying eggs. However, sexing this species reliably outside of spawning condition can be challenging even for experienced keepers.

Natural Habitat

Ctenops nobilis is found across a relatively broad but fragmented range in South and Southeast Asia. Its distribution encompasses the lowland regions of northeastern India – particularly the states of Assam, West Bengal, and Meghalaya – as well as parts of Bangladesh and western Myanmar. Within this range, it inhabits a variety of slow-moving or still freshwater environments, showing a strong preference for heavily vegetated habitats with abundant cover.

Typical habitats include shallow, slow-flowing streams, oxbow lakes, floodplain marshes, rice paddies, drainage ditches, and the margins of larger rivers where aquatic vegetation grows densely. The water in these environments is often stained with tannins from decaying organic matter, giving it a tea-coloured appearance. The substrate is typically composed of mud, silt, and decomposing leaf litter, which contributes to the soft, acidic to neutral water chemistry that characterises these biotopes.

The monsoon cycle plays a significant role in the ecology of these habitats. During the wet season, water levels rise dramatically, flooding adjacent areas and creating expansive, shallow, vegetation-rich environments that provide ample feeding and breeding opportunities. During the dry season, water recedes, concentrating fish populations into smaller pools and channels. This seasonal fluctuation means that the Frail Gourami is adapted to cope with some variation in water parameters, though prolonged exposure to poor water quality is detrimental.

As a labyrinth fish, Ctenops nobilis possesses an accessory breathing organ – the labyrinth organ – that allows it to extract oxygen directly from atmospheric air. This adaptation is crucial in its natural habitat, where dissolved oxygen levels can drop significantly, particularly in warm, stagnant, vegetation-choked waters during the dry season. In the aquarium, you will regularly observe the fish rising to the surface to take gulps of air, which is entirely normal behaviour.

The presence of dense aquatic vegetation, including floating plants, submerged grasses, and emergent marginal plants, is a defining feature of its habitat. These plants serve multiple functions: they provide cover from predators, create territories, support the invertebrate populations on which the fish feeds, and offer spawning sites. Replicating this densely planted environment is one of the most important aspects of keeping Frail Gouramis successfully in captivity.

Tank Size and Setup

A minimum tank size of 75 litres is recommended for a single specimen or a pair of Frail Gouramis. If you intend to keep a small group – which is preferable for observing natural behaviours – a tank of 120 litres or more is advisable. The footprint of the tank matters more than the height; a longer, shallower aquarium is more appropriate than a tall, narrow one, as this species primarily occupies the middle and upper water column and benefits from greater horizontal swimming space.

The aquascape should prioritise dense planting and abundant cover. Use a combination of rooted plants, floating plants, and driftwood to create a complex, sheltered environment. Cryptocoryne species, Vallisneria, Java Fern (Microsorum pteropus), and Anubias species are all excellent choices for background and midground planting. Floating plants such as Amazon Frogbit (Limnobium laevigatum), Salvinia, or Water Lettuce (Pistia stratiotes) are particularly valuable, as they dim the lighting, provide overhead cover, and help the fish feel secure. Frail Gouramis are notably shy and will remain perpetually stressed in sparsely decorated tanks with bright, unfiltered lighting.

Driftwood and dried Indian almond leaves (Terminalia catappa) serve a dual purpose: they provide additional hiding spots and visual barriers, and they release tannins into the water, gently lowering pH and staining the water a light amber colour that mimics the species’ natural blackwater or tea-stained habitats. The tannins also possess mild antibacterial and antifungal properties, which can benefit overall fish health.

The substrate can be fine gravel or sand, preferably in a dark colour to reduce light reflection from below, which can unsettle the fish. A layer of dried leaves scattered across the substrate completes the natural look and provides foraging opportunities as microfauna colonise the decomposing leaf matter.

Lighting should be subdued. If you are growing live plants that require moderate light, ensure that floating plants provide sufficient shade to create dappled, low-light areas where the gouramis can retreat. LED lighting with adjustable intensity or a dimmer is ideal. Avoid sudden changes in lighting; a gradual dawn-to-dusk transition reduces stress considerably.

Ensure the tank has a tight-fitting lid with minimal gaps. As a labyrinth fish, Ctenops nobilis must access the surface to breathe atmospheric air. A lid maintains a warm, humid layer of air above the water surface, preventing the fish from inhaling cold, dry air, which can damage the labyrinth organ and lead to respiratory problems. This is especially important in cooler climates or air-conditioned rooms.

Water Parameters

Temperature 20-26 °C
pH 6.0-7.5
General hardness (GH) 2-10 dGH
Carbonate hardness (KH) 2-6 dKH
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate Below 20 ppm

The Frail Gourami thrives in soft, slightly acidic to neutral water. While it can tolerate a range of conditions, the best results – including the most vibrant colouration and natural behaviour – are achieved in water on the softer, more acidic end of the spectrum. A pH of around 6.5 and a general hardness of 4-6 dGH represents an ideal target for most keepers.

Temperature management deserves particular attention with this species. Unlike many tropical fish that prefer consistently warm water at 26-28 °C, the Frail Gourami originates from subtropical regions that experience seasonal temperature variation. It is comfortable at temperatures ranging from 20 to 26 °C and may actually benefit from a slight seasonal cooling during winter months, down to around 20 °C, followed by a gradual warming in spring. Sustained temperatures above 28 °C should be avoided, as the species does not cope well with prolonged heat.

Water quality must be maintained at a high standard. Ammonia and nitrite must always read zero, and nitrate should be kept below 20 ppm through regular partial water changes. A weekly water change of 20-30% is a sensible baseline, though the exact frequency and volume will depend on stocking levels, filtration capacity, and feeding regimen. When performing water changes, ensure the replacement water is closely matched in temperature and chemistry to avoid shocking this sensitive species.

The addition of botanicals such as Indian almond leaves, alder cones, or peat filtration can help maintain the slightly acidic, tannin-rich conditions that this fish appreciates. If your tap water is naturally hard and alkaline, you may need to use reverse osmosis (RO) water remineralised with an appropriate product to achieve suitable parameters.

Filtration and Equipment

Filtration for Frail Gouramis should prioritise biological efficiency while producing minimal water flow. This species inhabits slow-moving to almost still waters in the wild and will become stressed if subjected to strong currents. A sponge filter is an excellent choice for smaller setups, providing gentle, effective biological and mechanical filtration with virtually no current. For larger tanks, a small external canister filter or hang-on-back filter with an adjustable flow rate is suitable, but the outflow should be diffused using a spray bar, lily pipe, or baffle to reduce water movement.

An air pump connected to a sponge filter or an airstone provides gentle oxygenation of the water column, though the fish’s labyrinth organ means it is less dependent on dissolved oxygen than many other species. Avoid excessive surface agitation, as this can dissipate the warm, humid air layer above the water that the fish relies upon when breathing at the surface.

A heater is generally required unless you keep the aquarium in a consistently warm room. Choose a reliable, adjustable heater rated for your tank volume. A heater guard is advisable to prevent the fish from resting against it and suffering burns, though this is less of a concern with the Frail Gourami than with some bottom-dwelling species. A thermometer – ideally a digital one for accuracy – should be used to monitor temperature continuously.

Lighting, as discussed in the tank setup section, should be subdued. A timer is helpful for maintaining a consistent photoperiod of around 8 to 10 hours per day. If using brighter lights to support plant growth, floating plant cover becomes essential to create the shaded conditions this species requires.

A tight-fitting lid or cover glass is non-negotiable. Beyond preventing the fish from jumping – a real risk when they are startled – the lid maintains the layer of warm, moist air above the water surface that is critical for the health of any labyrinth fish. In rooms where ambient temperatures fluctuate significantly, the lid becomes even more important.

Diet and Feeding

The Frail Gourami is primarily a carnivore and micropredator in the wild, feeding on small aquatic invertebrates, insect larvae, zooplankton, and tiny crustaceans. In captivity, this dietary preference presents one of the main challenges of keeping the species, as many specimens – particularly wild-caught individuals – can be reluctant to accept dried commercial foods.

Live and frozen foods should form the staple diet. Bloodworm (Chironomid larvae), daphnia, brine shrimp (Artemia), mosquito larvae, tubifex worms, and small glassworms are all eagerly accepted. Live foods are particularly valuable for newly acquired specimens that may be shy or slow to feed, as the movement of live prey triggers a strong feeding response. Frozen versions of these foods are a convenient and nutritionally adequate alternative once the fish have settled in and are feeding confidently.

Some keepers have success weaning Frail Gouramis onto high-quality micro pellets or slow-sinking granules designed for small carnivorous fish, but this is by no means guaranteed. If you wish to attempt this, introduce dried foods gradually alongside frozen or live foods, and be patient – it may take weeks or even months for the fish to begin accepting them. Even if they do accept pellets, live and frozen foods should remain a significant part of the diet to ensure optimal nutrition and condition.

Feed small amounts two to three times daily rather than one large meal. The Frail Gourami has a relatively small stomach and a fast metabolism, so frequent, modest feedings more closely replicate the continuous foraging behaviour it exhibits in the wild. Remove any uneaten food promptly to prevent water quality deterioration.

Variety is important. Offering a rotation of different live and frozen foods ensures a broad nutritional profile and helps prevent dietary deficiencies. Gut-loaded live foods – those that have themselves been fed nutritious foods before being offered to the fish – provide enhanced nutritional value.

Behaviour and Temperament

The Frail Gourami is a shy, retiring species that spends much of its time hovering amongst vegetation or drifting slowly through the middle and upper water column. It is not an active, constantly visible fish; rather, it tends to remain partially concealed, emerging cautiously to feed or explore. This secretive nature is part of its charm for experienced hobbyists but may frustrate those accustomed to bolder, more outgoing species.

In terms of conspecific behaviour, Frail Gouramis can be kept singly, in pairs, or in small groups. Males may display mild territoriality towards one another, particularly in confined spaces or during breeding periods, but aggression rarely escalates to the point of causing physical harm, provided the tank is sufficiently large and well-structured with visual barriers. In a well-planted tank of 120 litres or more, a group of four to six individuals can coexist peacefully, and the social interactions between them are far more interesting to observe than the behaviour of a solitary specimen.

Towards other species, the Frail Gourami is generally peaceful and inoffensive. However, it is easily intimidated by larger, more boisterous, or aggressive tank mates. If housed with overly active or competitive feeders, it may fail to obtain sufficient food and will retreat into hiding, eventually declining in condition. Choosing tank mates carefully is therefore essential.

One notable behaviour to watch for is the characteristic “head-standing” posture, in which the fish tilts its body at an angle, often head-down, amongst plant stems or driftwood. This appears to be a resting or camouflage posture and is entirely normal. Similarly, the fish regularly rises to the water surface to gulp air, which is standard labyrinth fish behaviour and not a sign of distress, provided water quality parameters are within acceptable ranges.

The Frail Gourami is also a surprisingly competent predator of very small organisms. While it poses no threat to appropriately sized tank mates, it will readily consume dwarf shrimp, newly hatched fry of other species, and small invertebrates. This predatory instinct can actually be beneficial in controlling pest snail populations, though it rules out cohabitation with ornamental dwarf shrimp such as Neocaridina or Caridina species.

Tank Mates

Selecting appropriate tank mates for the Frail Gourami requires careful consideration of its shy, peaceful nature and its preference for calm, low-flow environments. Ideal companions are small, non-aggressive species that occupy different areas of the tank and will not outcompete the Frail Gourami for food. Avoid large, boisterous, or fin-nipping species, as well as any fish that would create excessive water disturbance or territorial aggression.

Good tank mates

  • Harlequin Rasbora – A peaceful, small schooling fish that occupies the middle water column and thrives in similar soft, acidic water conditions.
  • Ember Tetra – Tiny, gentle, and unobtrusive, Ember Tetras are ideal dither fish that help draw out shy species without causing stress.
  • Pygmy Corydoras – These diminutive bottom-dwellers are peaceful and occupy a different zone of the tank, posing no threat or competition.
  • Kuhli Loach – A nocturnal, non-aggressive bottom-dweller that coexists well with quiet mid-water species in planted setups.
  • Sparkling Gourami – A small, peaceful anabantoid with similar water requirements and a calm demeanour that makes it a compatible companion.
  • Chocolate Gourami – Another shy, soft-water gourami species with overlapping habitat preferences, suitable in spacious, well-planted tanks.
  • Celestial Pearl Danio – A diminutive, peaceful species that adds colour to the middle and lower water column without disturbing timid tank mates.
  • Chili Rasbora – One of the smallest rasboras available, its tiny size and gentle nature make it an excellent companion in a softwater community.

Fish to avoid

  • Tiger Barb – A notorious fin-nipper with boisterous behaviour that would bully and stress the Frail Gourami relentlessly.
  • Convict Cichlid – Far too aggressive and territorial for any tank containing Frail Gouramis, with entirely incompatible care requirements.
  • Chinese Algae Eater – Becomes increasingly territorial and aggressive with age and may harass slow-moving, elongated fish.
  • Red Tail Shark – Highly territorial and aggressive towards fish occupying similar water column levels, causing chronic stress.
  • Giant Gourami – Grows far too large and would view the Frail Gourami as potential prey or a territorial rival.
  • Buenos Aires Tetra – A large, active, plant-eating tetra that is too boisterous and would outcompete the Frail Gourami at feeding time.
  • Oscar – A large, predatory cichlid entirely unsuitable for housing with any small, peaceful species.
  • Paradise Fish – Despite being a fellow anabantoid, its aggressive, territorial nature makes it a poor companion for the timid Frail Gourami.

Breeding

Breeding the Frail Gourami in captivity is a genuinely challenging undertaking that has been accomplished only sporadically. However, it remains one of the most rewarding aspects of keeping this species for those willing to invest the time, effort, and patience required. The most remarkable aspect of its reproductive biology is that Ctenops nobilis is a paternal mouthbrooder, a highly unusual trait among anabantoid fishes. Unlike the bubble-nesting behaviour exhibited by most gouramis, the male Frail Gourami incubates the fertilised eggs in his mouth until they hatch and the fry are free-swimming.

To encourage breeding, begin by conditioning a pair or small group with generous quantities of high-quality live foods over several weeks. Gradually lower the water temperature to around 20-22 °C to simulate a cooler period, then slowly raise it to 24-26 °C over a week or two, mimicking the onset of the warm, wet monsoon season that triggers spawning in the wild. Slightly softer, more acidic water – a pH of around 6.0-6.5 and GH of 2-4 dGH – appears to be beneficial.

Spawning behaviour involves an elaborate courtship display. The male intensifies his colouration and approaches the female with spread fins, performing a series of lateral displays and body undulations. If the female is receptive, the pair engage in a spawning embrace beneath the water surface or amongst vegetation. The embrace is similar to that of other anabantoids: the male wraps his body around the female, and eggs and sperm are released simultaneously. The eggs are relatively few in number compared to bubble-nesting species, typically numbering between 20 and 80 per spawning event.

After spawning, the male collects the fertilised eggs in his mouth. From this point, the male will not eat for the duration of the incubation period, which lasts approximately 12 to 17 days depending on temperature. During this time, the male should be disturbed as little as possible; excessive stress can cause him to swallow or spit out the eggs prematurely. Remove the female if she shows any signs of harassment towards the incubating male, and minimise maintenance activities such as water changes in the breeding tank during this period.

When the fry are released, they are small but relatively well-developed compared to the fry of many other gourami species. They will initially require very fine foods such as infusoria, paramecium, or commercially available liquid fry food. After a few days, they can graduate to freshly hatched brine shrimp nauplii and microworms. Growth is slow, and the fry are sensitive to water quality fluctuations, so small, frequent water changes with carefully matched parameters are essential during the rearing period.

Common Diseases

The Frail Gourami, like many wild-caught and uncommon species, can be susceptible to a range of health issues, particularly if water quality is not maintained or if the fish experiences chronic stress from inappropriate tank conditions or aggressive tank mates. Prevention through excellent husbandry is always preferable to treatment.

Bacterial infections are among the most common problems encountered. These may manifest as fin rot, body ulcers, or general lethargy and loss of appetite. Bacterial infections typically arise secondary to stress or poor water quality. Maintaining pristine water conditions, avoiding overcrowding, and providing a calm, well-structured environment are the best preventive measures. Treatment usually involves antibacterial medications, ideally in a separate hospital tank to avoid disrupting the biological filter in the main aquarium.

White spot disease (Ichthyophthirius multifiliis), commonly known as ich, can affect Frail Gouramis, particularly newly imported specimens that may be immunocompromised from the stresses of capture and transport. The characteristic white spots on the body and fins are usually easy to identify. Raising the water temperature to 28-30 °C for a short period, combined with the addition of aquarium salt or a proprietary ich treatment, is the standard approach. Note that this elevated temperature is above the species’ ideal range, so it should be applied only as a treatment measure and gradually returned to normal levels once the parasite has been eradicated.

Velvet disease (Oodinium), caused by a parasitic dinoflagellate, is another concern. It presents as a fine, gold or rust-coloured dusting on the skin and fins, often accompanied by clamped fins, flashing (rubbing against surfaces), and laboured breathing. Velvet can be more difficult to spot than ich in its early stages. Treatment involves dimming lights (the parasite is photosynthetic), raising temperature slightly, and administering a copper-based medication, though copper must be used cautiously as some fish and invertebrates are sensitive to it.

Internal parasites may be present in wild-caught specimens. Signs include weight loss despite a good appetite, white or stringy faeces, and general wasting. Antiparasitic medications containing praziquantel or levamisole can be effective. Quarantining all new arrivals for a minimum of two to four weeks in a separate tank before introducing them to an established community is strongly recommended, as this allows observation for signs of disease and prophylactic treatment if necessary.

Labyrinth organ damage can occur if the fish is forced to breathe cold, dry air – for instance, if the tank lacks a lid in a cool room. This may lead to respiratory distress and secondary infections. Ensuring a tight-fitting cover to maintain warm, humid air above the water surface is a simple but critical preventive measure.

FAQs

Is the Frail Gourami suitable for beginners?

No. The Frail Gourami is best suited to experienced aquarists who are comfortable maintaining stable, soft-water conditions and providing a diet of live and frozen foods. Its shy nature, reluctance to accept dried foods, and sensitivity to water quality and tank mate selection mean that newcomers to the hobby would be better served starting with hardier gourami species such as the Honey Gourami or Pearl Gourami before attempting Ctenops nobilis.

Can I keep Frail Gouramis with dwarf shrimp?

This is generally not advisable. Although the Frail Gourami is peaceful towards fish of similar size, it is a natural micropredator and will readily consume small shrimp such as Cherry Shrimp (Neocaridina davidi) or Crystal Red Shrimp (Caridina cantonensis). Larger Amano Shrimp (Caridina multidentata) may fare better due to their size, but there is still some risk, particularly with juveniles.

How can I tell if my Frail Gourami is male or female?

Sexing Frail Gouramis is difficult outside of breeding condition. Males tend to be slightly slimmer and may display marginally more vivid colouration, particularly along the flanks and fins. Females in breeding condition will appear noticeably fuller in the belly when carrying eggs. During active courtship, the behavioural differences become more apparent, as the male performs elaborate displays and will ultimately be the one to incubate the eggs in his mouth.

Why does my Frail Gourami hide all the time?

Persistent hiding is usually a sign that the fish does not feel secure in its environment. Common causes include insufficient plant cover, overly bright lighting, aggressive or overly active tank mates, and tanks that are too open or sparsely decorated. Adding more floating plants, reducing light intensity, and ensuring compatible tank mates should encourage the fish to venture out more frequently. Newly acquired specimens may take several weeks to settle in fully.

Where can I buy Frail Gouramis?

The Frail Gourami is genuinely uncommon in the aquarium trade and is rarely stocked by mainstream retailers. Your best options are specialist importers of wild-caught Asian fish, dedicated online aquatic retailers, or aquarist society swap meets and forums. Some hobbyist breeders occasionally produce captive-bred specimens, which are preferable as they tend to be hardier and more adaptable to aquarium conditions than wild-caught fish. Patience and networking within the hobby are often required to source this species.

  • Chocolate Gourami – Another shy, soft-water mouthbrooding gourami with similar care requirements and temperament, ideal for comparison.
  • Liquorice Gourami – A fellow uncommon anabantoid from Southeast Asia that shares the Frail Gourami’s preference for soft, acidic, tannin-stained water.
  • Sparkling Gourami – A more widely available small gourami species that makes an excellent tank mate or alternative for those seeking a peaceful anabantoid.
  • Honey Gourami – A hardier, more beginner-friendly gourami that serves as a good stepping stone before attempting more demanding species like Ctenops nobilis.
  • Pearl Gourami – A popular, beautiful gourami species that thrives in similar planted setups, useful for understanding general gourami husbandry principles.

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