Pao Palembangensis Pufferfish Care Sheet

Pufferfish Enthusiasts Worldwide
Apr 10, 2020
23 min read

Updated: Oct 20

This care sheet is written to provide the optimal care for this species of fish.

Pufferfish Enthusiasts Worldwide endeavours to inspire and promote the highest standards of care - not basic or minimum care - using the best evidence available at the time.

Introduction

The Pao palembangensis is one of the most distinctive and charismatic freshwater puffers. Native to Southeast Asia, it occurs in Thailand, Laos, Malaysia, and Indonesia, with notable records from Sumatra that echo in its name.

In the wild, it inhabits slow-flowing rivers, lakes, and backwaters, often keeping close to cover where its marbled patterning blends into the substrate and leaf litter.

The species was first described in 1850 by the Dutch ichthyologist Pieter Bleeker, whose work laid much of the foundation for modern tropical fish taxonomy. At the time, almost all puffers were grouped under the vast, catch-all genus Tetraodon. As research advanced, P. palembangensis was later reassigned to Monotrete (also written as Monotretus in older literature), a genus that temporarily gathered a range of Southeast Asian forms thought to be related. Later study, however, showed that Monotrete contained species that were only superficially similar and not truly close relatives.

A full taxonomic revision of the puffer family in 2013 finally untangled these relationships. It restored Pao as a valid genus encompassing several riverine species from the region, among them P. palembangensis, P. suvattii, P. baileyi, and others now familiar to aquarists. Since then, Pao has been firmly established in scientific literature and is recognised as the correct classification for these distinctive freshwater puffers.

Among its kin, P. palembangensis stands out immediately. Its broad head, arched back, and expressive, ruby-tinted eyes give it a presence that feels ancient and almost deliberate. The patterning varies from fish to fish, swirling between pale tan and deep brown, but even with this variation the overall shape and posture leave no doubt about its identity.

Adult specimens reach around 19–20 cm in standard length, forming a heavy, muscular body adapted for ambush. In the wild, it spends long periods motionless, sometimes half-buried, watching quietly until prey strays too close. There are even accounts of this species feigning death before springing to life in a sudden, decisive lunge: behaviour that perfectly illustrates its calculating nature.

It is best known in the trade as the Humpback Puffer or Dragon Puffer, both long-established names that capture its appearance and bearing. The term “red-eyed puffer,” however, is better avoided; it has been applied to several unrelated Pao species and easily causes confusion.

The scientific name itself is a simple geographical tribute. Palembangensis combines Palembang (the capital of South Sumatra) with the Latin -ensis, meaning “from” or “originating in.”

Despite its popularity among enthusiasts, the aquarium trade still depends entirely on wild fish. There are no verified records of successful captive breeding, and no organised propagation projects have been established. Most exports originate from Thailand, Sumatra, and Borneo, where collectors work through established ornamental-fish networks. Even so, export numbers remain small compared with more manageable puffers, which is a reflection of the species’ size, temperament, and specialist care requirements.

In the wild

Across Southeast Asia, Pao palembangensis inhabits the quiet, lowland waters that thread through forests and floodplains. It is a fish of stillness and shadow, found in slow rivers, oxbow lakes, and meandering backwaters where the current barely moves and the substrate is soft beneath layers of silt and leaves. Fallen wood, tangled roots, and drifts of decaying foliage form its natural world. The water here is often the colour of dark tea, stained by tannins and humic acids that leach from forest debris, and the light that filters through the canopy above is dim and amber.

Its confirmed range extends across Thailand, Laos, Peninsular Malaysia, and Indonesia, with reliable records from both Sumatra and Borneo. Older checklists have mentioned Cambodia and Vietnam, but those reports almost certainly stem from misidentified species. In the Mekong basin, for instance, Pao suvattii and Pao baileyi occupy similar habitats and can easily be mistaken for P. palembangensis by untrained observers.

The waters it calls home are warm and soft, changing with the rhythm of the seasons. During the rains, temperatures hover around 25–30 °C; in shaded forest creeks, they can dip a little lower. Conductivity readings from comparable habitats in Sumatra and southern Thailand fall between 30 and 150 µS/cm, water that is very low in dissolved minerals, rarely exceeding 4 °dH general hardness or 2 °dH carbonate hardness. The pH is slightly acidic to neutral, typically around 5.8–7.2, though it can drift outside this range as floods rise and retreat. Dissolved oxygen varies widely: brisk channels may exceed 7 mg/L, while stagnant pools on the floodplain can drop to 3 mg/L or even less.

Life in these environments follows a predictable rhythm. When the monsoon arrives, floodwaters spill into the surrounding forest, turning the leaf litter into a rich, submerged world alive with worms, insects, and crustaceans. P. palembangensis moves in to feed, gliding between roots and stems in search of prey. As the waters withdraw, it returns to deeper, permanent channels where fallen branches and organic debris provide cover and hunting ground alike.

Its behaviour mirrors its surroundings: deliberate, patient, and built on camouflage. Rather than chase, it waits. A passing shrimp or fish is met with a sudden forward surge, a flash of motion that ends as quickly as it began. Collectors describe it as solitary and territorial, each fish keeping its own small patch of quiet water.

Warm, mineral-poor conditions, gentle flow, and abundant organic cover define the ecological niche of Pao palembangensis. It thrives in places of stillness and concealment, environments shaped by the slow chemistry of decay and the rhythm of seasonal flood. Within that quiet world, this puffer has evolved into a master of patience, blending perfectly with the forest floor.

Diet in the Wild

There are no published gut-content studies for Pao palembangensis, so its diet must be pieced together from what we know of its relatives, the structure of its habitat, and the anatomy of its jaws. Like other members of Pao, it has heavily fused dental plates and a broad, muscular mouth, a design made for cracking shells rather than chasing fish.

In the wild, the Dragon Puffer spends much of its time close to the bottom, hidden among leaves, wood, and fine silt. It waits rather than searches, striking only when something edible strays within range. Field collectors describe this same behaviour in several congeners found in comparable habitats across Southeast Asia.

Its likely prey reflects what lives in those quiet floodplain margins: freshwater snails, small crabs, insect larvae, and worms that burrow through the soft substrate. Families such as Viviparidae, Thiaridae, and Planorbidae provide an abundance of snails, while small crabs of the genera Parathelphusa and Somanniathelphusa scuttle between roots and leaf litter. Insect larvae from Chironomidae, Odonata, and Ephemeroptera round out the picture, all common components of the benthic fauna in these systems and all perfectly suited to the crushing strength of the puffer’s beak.

Seasonal changes likely shift its feeding habits. During the rains, when floodwaters spread through the forest and micro-crustaceans swarm among submerged vegetation, the fish probably takes softer, more mobile prey. As the floods recede and the backwaters contract, it turns to the snails, crabs, and annelids that remain in the deeper, oxygen-poor pools. Such transitions mirror the flood-pulse cycles that shape most Southeast Asian river life.

Occasional fish predation is certainly possible, but not central to its ecology. Related species, including Pao suvattii, have been recorded taking small fish when the opportunity arises. Observers of P. palembangensis have even noted its peculiar habit of feigning death, lying still and pale on the bottom until a curious shrimp or fish ventures too close, only to be seized in an instant.

Chemical evidence supports this interpretation of its diet. Within Pao, two distinct toxin lineages are known. The marine-associated group accumulates tetrodotoxin (TTX), while the strictly freshwater Mekong species, including P. palembangensis, carry saxitoxin (STX) and its analogues. Analyses of wild specimens from Thailand and Indonesia have found these compounds concentrated in the skin and ovaries, with TTX consistently absent. The toxins originate through the food web rather than within the fish itself: cyanobacteria and associated bacteria generate saxitoxins, which pass upward through snails, crustaceans, and other benthic invertebrates to the predator that feeds on them.

Taken together, the evidence presents Pao palembangensis as a slow, deliberate hunter shaped by its environment. It feeds mainly on the hard-shelled and soft-bodied invertebrates of the forest floor, with the occasional small fish taken only when opportunity makes it worthwhile.

Conservation Status

Pao palembangensis has not yet been evaluated by the IUCN Red List, and there is no current evidence to suggest that wild populations are in decline. Its range across mainland and island Southeast Asia remains broad, and it continues to be collected in several parts of its distribution. Nevertheless, the lowland rivers and floodplains this species depends are among the most ecologically vulnerable in the region. Deforestation, agricultural runoff, and river modification for irrigation and hydroelectric schemes have all altered water chemistry and habitat structure in places where the species occurs. Although these pressures are widespread, their direct impact on P. palembangensis populations has not been formally assessed.

Field and export records indicate that the species remains locally common but rarely abundant. Its solitary and territorial nature means individuals are seldom found close together, even in healthy populations. This gives the impression of scarcity, although the species is likely more widespread than casual observation suggests.

The species is not listed under CITES, and there are no national restrictions that prohibit its export. Its long-term sustainability, therefore, depends on responsible collection, careful handling, and good captive care. Each fish taken from the wild may be several years old, and success in the aquarium depends on providing the correct environment, diet, and space. When these needs are met, P. palembangensis can live for a decade or more and develop a strong recognition of its keeper.

In the Aquarium

Among the river puffers of Southeast Asia, Pao palembangensis is the one you’ll see most often in the hobby. There’s a reason for that. It’s striking, smart, and surprisingly adaptable once it feels at home.

All of the fish you’ll find for sale still come from the wild, mainly Thailand, Sumatra, and Borneo, but they usually settle well if the tank feels familiar and calm.

The Dragon Puffer’s temperament is quiet but alert.

It watches more than it moves. Most of the day, it sits half hidden among roots or under driftwood, keeping an eye on everything nearby. When the light softens in the morning or evening, it becomes more active, gliding through its territory with slow, careful motion.

You’ll notice that it seems to think before every move. Success with this fish really depends on building that same sense of stillness and security in its tank.

Keep the lighting gentle. A muted glow through floating plants works best, giving the tank a shaded look that feels natural to the fish. Bright, direct light tends to push it back into hiding, but under softer light, it relaxes and moves with that deliberate, almost thoughtful rhythm that defines the species.

This isn’t a fish for bare tanks. It needs texture and depth to feel at ease.

Start with fine sand scattered with leaves, seed pods, and small twigs to create a soft, lived-in base. Then add plenty of structure: driftwood, roots, and curved branches that break up sightlines and form small caves and shaded corners. Smooth stones can help mark out quiet resting spots or borders between areas the fish might claim as their own.

Planting adds the final touch. Use hardy, shade-tolerant species like Hygrophila polysperma, Ceratopteris thalictroides, or Limnophila sessiliflora to give depth and movement. Broader-leaved plants such as Anubias barteri, Echinodorus bleheri, and Cryptocoryne wendtii offer cool hiding spaces underneath. A few floating plants such as Salvinia natans or Limnobium laevigatum will soften the light and complete that calm, dappled surface you see in forest backwaters.

Once surrounded by this kind of setup, P. palembangensis begins to change. It grows bolder, curious, almost watchful. You’ll see it studying your movements from the shadows or following you along the glass. Over time, it learns its routine and starts waiting at its favourite spot when feeding’s due. It’s one of those fish that notice you more than you might expect.

Water flow should be slow and steady, just enough to keep oxygen moving and debris from settling. Too much current unsettles it. A quiet system with a good external filter suits it best, like the still, clear backwaters it came from.

When everything is balanced, light, space, and flow work together, this species shows its true nature. Calm. Measured.

A little cautious, but aware of everything. It’s not a fish that wins you over with colour or speed, but with quiet presence. Give it peace and stability and it will repay that trust with a kind of awareness that feels almost personal.

Substrate

You’ll notice sooner or later that Pao palembangensis likes to wallow. Not often, but every so often it will lower itself into the sand, just enough to disappear except for the eyes. It’s one of those small, natural things that show when the fish feels calm.

For that reason alone, it’s worth getting the substrate right.

Soft sand is the best choice. A fine river or silica sand about five centimetres deep works well. It lets the fish settle in safely without scratching itself. Coarse gravel and aqua soils might look tidy, but they’re too rough and can mark the skin. Smooth sand feels better under the fish and gives the tank that soft, natural look that just fits.

To maintain the substrate:

Keep the sand bed 2–5 cm deep in most areas, adding more only in favoured wallowing sites.
Stir or rake sections during weekly water changes to release trapped gases and circulate oxygen.
Ensure strong water movement across the surface to prevent detritus from settling.
When siphoning, vacuum lightly over the surface rather than disturbing the bed deeply each time.

When it’s all set up properly, the substrate becomes part of how the fish lives, not just what it sits on. Watching a Dragon Puffer ease down into the sand and vanish is oddly peaceful. It’s a sign the fish feels safe, at home, and in rhythm with its surroundings.

Tank size

Pao palembangensis is a largely sedentary species that spends much of its time resting close to the substrate or lying among roots and driftwood. In the wild, it moves slowly and deliberately, conserving energy and relying on ambush tactics rather than pursuit. This lifestyle means it does not require expansive open water, but it does need stability, structure, and space to establish a defined territory. While not a species that demands an oversized aquarium, P. palembangensis thrives when given room to explore a carefully arranged habitat.

A single adult should be kept in a tank measuring at least 80 cm in length and 35–40 cm front to back, with a height of around 40 cm.

This equates to a volume of approximately 110–120 litres (29–32 US gallons), which provides ample space for sand depth, planting, and natural cover while ensuring stable water chemistry.

As with all puffers, a larger aquarium offers clear advantages. Increased water volume improves waste dilution, enhances filtration performance, and allows for more elaborate aquascaping. In a spacious, well-structured tank, P. palembangensis displays noticeably greater confidence, often venturing from cover to observe activity beyond the glass. Its calm awareness and measured movements make it an especially rewarding species to keep when given the room to behave naturally.

Water values

Maintain the following water parameters:

pH: 6.5–7.5
Temperature: 24–28 °C
Ammonia (NH₃/NH₄⁺): 0 ppm
Nitrite (NO₂⁻): 0 ppm
Nitrate (NO₃⁻): Below 15 ppm (ideal)
General Hardness (GH): 2–6 dGH typical

Why these numbers?

These recommendations reflect the conditions recorded across the river systems of Thailand, Peninsular Malaysia, Sumatra, and Borneo, where Pao palembangensis inhabits slow, shaded waters beneath forest canopies. Surveys of these habitats describe warm, soft to moderately mineralised water with a neutral to slightly acidic reaction. Conductivity readings from these lowland streams and floodplain channels typically fall between 30 and 150 μS/cm, equating to roughly 1–6 °dGH.

Temperatures in these regions remain stable throughout the year, commonly between 25 and 30 °C, with minimal seasonal change. The recommended aquarium range of 24–28 °C sits comfortably within this band, warm enough to mirror tropical conditions while preserving oxygen balance and stable metabolism. Cooler water can slow digestion and suppress feeding, whereas prolonged heat above 29 °C risks oxygen depletion and stress.

A pH of 6.5–7.5 reflects the slightly acidic to neutral chemistry of its natural environment. Mid-range values around 6.8–7.0 tend to produce the best long-term results.

Ammonia and nitrite must remain at 0 ppm, as puffers are extremely sensitive to nitrogenous waste. Even trace levels can cause gill irritation and lead to a rapid decline.

Nitrate should stay below 15 ppm, ideally under 10 ppm, serving as an indicator of water cleanliness rather than direct toxicity. Regular, substantial water changes are the simplest and most reliable safeguard.

These values mirror the calm, warm, and softly mineralised waters that define the species’ natural range. When maintained with consistency and cleanliness, they allow Pao palembangensis to display its full poise and personality: a patient, deliberate hunter perfectly adapted to the tranquil rivers of Southeast Asia.

Tankmates

Pao palembangensis should be regarded as a solitary species.

In the wild, adults live alone among roots and submerged wood, defending small territories along the quiet margins of rivers and forest backwaters. This instinct for isolation carries into captivity, where other fish are almost always viewed either as food or as a source of stress.

Smaller fish are treated as prey. The Dragon Puffer is an efficient ambush hunter capable of delivering a sudden, decisive strike. Any tankmate small enough to fit into its mouth is likely to be eaten, often without warning. Size offers little protection; even fast or midwater species can be taken once the puffer becomes settled and territorial.

Larger or more active companions tend to provoke the opposite response. Instead of attacking, the puffer withdraws, becoming increasingly reclusive. Over time, this stress reaction can lead to appetite loss, lowered immunity, and a gradual decline in health.

For these reasons, P. palembangensis should always be housed alone. Solitary care allows it to relax, explore, and display the calm, intelligent behaviour for which the species is valued. In a quiet, well-structured aquarium, it becomes confident and observant, responding to its keeper with remarkable awareness.

When kept alone, Pao palembangensis thrives. Its movements become measured and assured, its colours deepen, and its behaviour reflects the quiet confidence of a predator at ease in its environment. This is not a fish for community tanks, but for those who appreciate the subtle intelligence and presence of a true solitary hunter.

Sexual Dimorphism

There are no reliable external features that distinguish male from female Pao palembangensis. In both the scientific literature and the aquarium trade, the species is generally regarded as sexually monomorphic.

Some keepers have noted that females may appear slightly rounder when viewed from above, especially when well-fed or carrying eggs, while males can seem slimmer with a flatter underside. However, these observations are inconsistent and cannot be used to determine sex with confidence. Body shape in this species varies naturally with age, diet, and condition, making visual comparison unreliable.

No differences in colouration, fin shape, or markings have been recorded, and no verified accounts of captive breeding exist to confirm any behavioural dimorphism. As a result, the only certain means of identifying sex is by internal examination, which is neither practical nor ethical for living specimens.

Until further study or successful breeding sheds light on the subject, Pao palembangensis should be considered sexually indistinguishable in outward appearance.

Notable behaviour

Pao palembangensis is calm by nature but always aware. Most of the time it lies still among roots or driftwood, half hidden by leaves, its eyes following whatever moves nearby. It wastes no energy. Every movement has a reason, and when it decides to act - to feed, explore, or simply look back at you - it does so with quiet confidence.

To someone seeing it for the first time, it can seem lazy or inactive. It isn’t. That stillness is how this fish survives. In the shaded rivers of its home range, it depends on patience rather than speed. It waits for the right moment and then strikes. In an aquarium, that same behaviour becomes a calm, measured presence once the surroundings feel safe.

When it settles, the Dragon Puffer begins to notice everything. It learns routines fast, recognising its keeper and often coming forward when it senses food is near. Some will even follow your hand along the glass or hover at a favourite spot when feeding time approaches. Each individual has its own rhythm and quirks.

Still, its awareness has another side. Too much change - a new layout, bright light, sudden movement - can unsettle it. A stressed P. palembangensis tends to withdraw rather than lash out. It will stay hidden for days, refusing food until it feels secure again. Gentle light, quiet surroundings, and a steady routine are what bring it back out.

In a stable, well-kept aquarium, this fish shows its true personality. It is curious but not restless, alert yet composed. Hours may pass with it simply watching, studying its world as if weighing every detail. That stillness is part of its charm, not a sign of dullness, and it’s what separates it from faster, more reactive puffers.

Once it trusts you, something changes. It begins to wait for you, react to movement, and even seem to anticipate your next action. It is not a fish to be handled or fussed over, but one to be observed quietly and appreciated for what it is. Those who take the time to understand it often find themselves forming a quiet bond: not through touch, but through recognition.

Beneath the heavy frame and wary eyes is a creature of intelligence and restraint. Given space and consistency, the Dragon Puffer reveals an unexpected depth of character, the kind that leaves a lasting impression on anyone who earns its trust.

Feeding

Feeding Pao palembangensis takes time and a calm hand. It isn’t a fish that eats on impulse. Most of the time, it just watches, hovering still, eyes shifting as it studies what’s in front of it. Then, without warning, it strikes. Quick. Clean. And then perfectly still again.

In the wild, this species hunts close to the bottom where the light fades and the silt settles.

It slides between fallen branches and leaf litter, searching for snails, small crabs, and insect larvae buried in the debris. Its mouth tells the story better than anything else. The jaw is strong and heavy, the teeth fused into a beak made for crushing hard shells and scraping at carapaces. It isn’t built for chasing fish. It prefers to take whatever crawls too close.

Field studies back this up. Wild fish have tested positive for tetrodotoxin (TTX), the same chemical found in many marine puffers. The toxin doesn’t come from the fish itself but from bacteria that live in the environment. Snails and crustaceans grazing on biofilm pick it up first, and when the puffer eats them, it takes in the toxin too. In a way, the chemistry of its body mirrors the chemistry of its prey.

Across its natural range, the likely food list includes viviparid and bithyniid snails like Filopaludina martensi and Bithynia siamensis goniomphalos, small freshwater crabs from Somanniathelphusa, and the larvae of midges and mayflies. These species thrive in the same warm, shaded floodplains and backwaters where the Dragon Puffer is found.

In captivity, the goal is to capture that same rhythm. Offer foods that have some resistance to them, not just soft fare that disintegrates. Snails are perfect. So are small pieces of worm or crab. Texture matters. A little variety helps too. Over time, it will learn the pattern of feeding and respond with quiet confidence.

Recommended Foods

Freshwater snails of varying sizes (ramshorn & pond snails)
Crayfish or crab legs from freshwater sources, offered in small pieces
Gut-loaded earthworms
Gut-loaded cockroaches, locusts, and crickets.
Occasional thiaminase-free fish fillet (e.g., tilapia, pollock, or smelt) for variety

Feed no more than three or four times per week. Occasional fasting days help to support digestion and prevent fatty buildup. This species digests slowly, and overfeeding quickly compromises water quality.

Avoid soft marine items such as shrimp, mussels, or clams, which are nutritionally imbalanced for this species and excessively rich in thiaminase.

Suggested Feeding Breakdown

To maintain balance and variety while reflecting the natural diet structure, the following approximate ratios are recommended:

25% freshwater snails and other suitable molluscs
25% crustaceans (crab & crayfish pieces)
30% worms and insect larvae (earthworms, blackworms, bloodworms)
15% thiaminase-free fish and soft protein
5% enrichment foods (small aquatic insects, daphnia, or occasional treats)

Feeding Fish

Fish flesh can be used sparingly to add variety to the diet of Pao palembangensis, but it should never form a major part of its feeding routine. In the wild, this species preys mainly on aquatic invertebrates and only occasionally consumes small fish. The goal in captivity is to maintain that same natural balance.

When using fish, it is essential to select thiaminase-free species. Thiaminase breaks down vitamin B₁ (thiamine), and long-term exposure can lead to deficiency, appetite loss, and neurological problems.

Recommended Fish Species

The following thiaminase-free and nutritionally safe choices can be used occasionally:

Tilapia (Oreochromis spp.)
Trout (Oncorhynchus mykiss)
Cod (Gadus morhua)
Pollock (Pollachius spp.)
Haddock (Melanogrammus aeglefinus)
Catfish (Ictalurus or Pangasius)
Pike or Perch, when cleanly sourced from freshwater

Frozen Pond Smelt (Hypomesus olidus) is also suitable, as it is thiaminase-free and appropriately sized. However, avoid Rainbow Smelt (Osmerus mordax), which contains thiaminase.

Foods to Avoid

Do not feed goldfish, minnows, anchovies, sardines, herrings, or most other smelts. These are thiaminase-positive species and unsuitable for long-term use.

Preparation

Because most market fish are too large to feed whole, proper preparation is important:

Remove the head, fins, and internal organs.
Fillet the fish, leaving scales and skin intact.
Cut fillets into bite-sized chunks that can be swallowed within one minute.
Freeze prepared pieces for at least seven days to kill parasites.
Store frozen portions for up to three months and thaw naturally in cool water before feeding.

Offer fish flesh no more than once every one to two weeks, alternating with the invertebrate-based foods that form the main diet. Feed using tongs to control portion size and prevent waste.

Pao palembangensis digests soft protein slowly, and excessive fish flesh can lead to poor water quality or fatty buildup. When used occasionally and prepared correctly, it adds valuable variety to the diet without compromising health or behaviour.

Feeder fish

Using live feeder fish might sound tempting, especially when a new Pao palembangensis refuses food, but it’s a mistake most experienced keepers only make once. Feeder fish are almost always raised in poor conditions, and that shows. They often carry a cocktail of parasites like Ichthyophthirius multifiliis (Ich), Trichodina, Gyrodactylus, Dactylogyrus, or Camallanus worms. On top of that, they frequently harbour bacterial infections such as Flavobacterium columnare (Columnaris). Adding one to your aquarium is a gamble you can’t really win.

Even if you dodge disease, live prey creates a different kind of problem. Puffers are clever, and they learn fast. Once they associate food with motion, they can become fixated on it. The result is a fish that refuses frozen or prepared foods and may go on long hunger strikes when the live supply dries up. It’s a pattern that’s frustrating for both fish and keeper.

A better approach is to offer fresh or frozen foods from the start. Thiaminase-free fish fillet, small pieces of frozen-thawed freshwater crab or crayfish, and gut-loaded worms or snails all work beautifully. These provide the same nutrition and feeding response without introducing the risk of parasites or infection.

Given a little time and consistency, P. palembangensis will adapt. Once it starts recognising the feeding tongs and settles into a routine, it accepts non-living foods with confidence. In truth, live feeders bring more harm than help. They’re unnecessary for success and far more likely to cause trouble than solve it.

Tong Training

For keepers of Pao palembangensis, tong training quickly becomes one of the most useful skills to learn. It is far more than a feeding trick. Done well, it becomes a quiet way of building communication and trust between you and the fish.

Most individuals enter captivity straight from the wild. They arrive wary, still wired for survival, often refusing anything that does not move on its own. Some will fast for days or even weeks. It can be frustrating, but it is normal behaviour for a puffer that has never known glass walls or human hands.

Tong training gives you a simple, gentle way through this stage. The goal is not to rush feeding but to create a routine that feels safe and predictable. When food is offered with the same slow movement and from the same direction each time, the fish starts to associate those tongs with security and food rather than threat. Over time, it will watch for them, hover in place, and eventually take the first bite.

Once that bond forms, everything else becomes easier. You can control the size of each portion, make sure nothing is left to rot, and check that the fish is eating properly. It also keeps the tank cleaner and lets you spot problems early (appetite, hesitation, colour change), all the small signals that matter with this species.

Behaviourally, tong training does something deeper. It builds confidence. A fish that once hid at the back will begin to glide forward when you approach, waiting patiently near its chosen feeding spot. It is the first sign that it feels secure enough to interact.

For an animal as intelligent and cautious as Pao palembangensis, this simple practice becomes much more than feeding. It turns mealtime into quiet conversation, a moment of recognition between keeper and fish, and one of the surest signs that the animal has truly settled in.

Filtration & Tank Maintenance

Although Pao palembangensis is not an active swimmer, it still produces a surprising amount of waste for a single fish. In a confined system, that waste builds up quickly. Unless the aquarium has strong biological filtration and a steady maintenance routine, the water can deteriorate long before it looks dirty.

For most setups, a large external canister filter is ideal. The combination of high biological volume and fine mechanical filtration keeps the water both clear and stable. In bigger tanks, a sump system adds another layer of reliability. It increases total water volume, improves gas exchange, and allows heaters and other equipment to be tucked neatly out of sight, leaving the display uncluttered.

Water movement should be slow and steady, never harsh. A gentle, continuous flow carries oxygen through every part of the tank and stops debris from collecting in dead spots. This creates the clean, calm environment that the species prefers. When directing outflow, aim across the surface rather than along the substrate to preserve that sense of stillness the fish seems to appreciate.

No filter, however efficient, can replace a simple maintenance routine. Regular water changes, light substrate cleaning, and a watchful eye remain the foundations of good care.

Clean, stable water is the foundation of success:

Keep nitrate below 15 ppm, ideally closer to 10 ppm.
Change at least 50% of the water weekly, increasing frequency during periods of heavier feeding.
Lightly vacuum the substrate during each change, paying special attention to areas beneath driftwood and plants where waste tends to collect.
Ensure good surface agitation to maintain high oxygen levels, especially in warmer water.

When the filtration system is mature and maintenance is consistent, the Dragon Puffer thrives. Clear water, stable chemistry, and a tranquil environment support both its physical health and its naturally composed behaviour.

Why Keep Nitrates Low?

Like all members of the Pao genus, Pao palembangensis is highly sensitive to nitrate buildup. Even low concentrations that many other fish tolerate can cause long-term stress in this species, leading to subtle but progressive health decline.

Research on freshwater fishes has shown that chronic nitrate exposure can cause:

Suppressed immune function, increasing vulnerability to disease
Reduced growth and feed efficiency, limiting condition and vitality
Shortened lifespan and long-term health decline

In the wild, P. palembangensis inhabits slow-moving forest streams and floodplain backwaters where rainfall and seasonal flooding continually renew the water column. These conditions keep dissolved waste extremely low. In captivity, that natural renewal must come from the keeper. Regular water changes, mature biological filtration, and restrained feeding are the key to maintaining the purity and stability this species depends on.

For the Dragon Puffer, clean, low-nitrate water does more than sustain health. It supports confidence, colour, and calm behaviour. When maintained in stable, pristine conditions, this species shows its full personality: observant, composed, and quietly responsive to its surroundings.

You can read our article on nitrate here.

Inflation

Like all puffers, Pao palembangensis can inflate its body when threatened. This defensive behaviour is a last resort, used only in moments of extreme fear or physical restraint. In nature, inflation helps the fish deter predators by making itself appear larger and more difficult to swallow.

In captivity, inflation should never be encouraged. Forcing a puffer to inflate for photographs or demonstrations causes intense stress and can be dangerous to its health. During inflation, the fish rapidly gulps water (or air, if removed from the tank) into a specialised stretchable stomach. If performed in air, this can lead to internal injury, buoyancy issues, or even death if air becomes trapped.

Occasionally, keepers may observe what is known as “practice puffing.” A relaxed P. palembangensis may briefly inflate in place with no clear trigger, then gently deflate a few seconds later. This behaviour is thought to help stretch the skin and exercise the muscles involved in inflation. Short, controlled puffs of this kind are harmless and not a cause for concern.

True defensive inflation, by contrast, occurs only when the fish feels startled or threatened. If this happens, the best response is simply to remain still and allow it to calm naturally. The fish will deflate on its own once it feels secure.

Prolonged or repeated inflation is usually a sign that something is wrong. Common causes include:

Poor water quality (ammonia, nitrite, or high nitrate)
Sudden lighting changes or vibration near the tank
Stress from aggressive tankmates
Rough handling or poor transfer technique

When P. palembangensis must be moved, it should always be transferred while fully submerged. Gently guide it into a water-filled container rather than lifting it with a net. Keeping the fish underwater prevents panic and eliminates the risk of air being drawn into the body.

A healthy, settled Dragon Puffer rarely inflates outside of brief practice puffs. In a calm, clean, and stable environment, the need for this extraordinary defence almost disappears: a true sign that the fish feels safe and at home.

Toxicity and Toxin Origin

Wild Pao palembangensis is now known to contain saxitoxin (STX) and related paralytic shellfish toxins (PSTs), rather than tetrodotoxin (TTX). This toxin profile places it firmly within the freshwater lineage of the genus Pao, alongside species such as P. suvattii and P. turgidus.

Field studies conducted in Thailand and Cambodia have confirmed the presence of STX, decarbamoyl-saxitoxin (dcSTX), and neo-saxitoxin (neoSTX) in P. palembangensis. The highest concentrations were recorded in the skin and ovaries, with TTX consistently absent. These findings distinguish the species from its marine relatives and demonstrate that the toxins originate through diet rather than internal synthesis.

In the wild, the pathway begins with cyanobacteria and toxin-producing bacteria that inhabit biofilms on submerged surfaces. These microorganisms are consumed by grazing invertebrates such as snails and small crustaceans, which then pass the compounds upward through the food web. Over time, the toxins accumulate in the tissues of the pufferfish, providing a potent chemical defence against predators.

In captivity, this ecological chain is broken. Aquarium diets lack the environmental bacteria and toxin vectors required for accumulation, and captive fish maintained on clean, prepared foods are completely non-toxic. The toxins cannot be transmitted through water or contact, and the fish poses no risk to its keeper.

Disclaimer

The health and husbandry information provided in this guide is intended for educational purposes only. It should not be taken as, or replace, the advice of a qualified aquatic veterinarian.

If your pufferfish shows signs of illness or is experiencing a medical emergency, seek assistance from an experienced aquatic veterinary professional without delay.