Tetraodon Schoutedeni Pufferfish Care Sheet

Macauley Sykes
Aug 1, 2020
24 min read

Updated: Sep 10

This care sheet is written with the aim of providing 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.

The Spotted Congo Puffer (Tetraodon schoutedeni) is a small, charismatic freshwater pufferfish endemic to the Congo Basin of Central Africa.

First described in 1926 and named in honour of the Belgian zoologist Henri Schouteden, this species is instantly recognisable by its leopard-like spotting, rounded body, and ever-curious expression. Among aquarists, it is admired not only for its beauty but also for its unique blend of intelligence and manageable size.

Adults typically reach 8–10 cm (3–4″), making them the smallest of the African freshwater puffers and far easier to house than giants such as Tetraodon mbu. Their modest size, coupled with a lifespan of well over 8 years in captivity, makes them an ideal “odd-ball” species for dedicated keepers prepared to meet their specialised needs.

What sets the Spotted Congo Puffer apart from many of its relatives is its temperament. While all puffers are predators and capable of aggression, T. schoutedeni is widely regarded as one of the more peaceful and sociable freshwater pufferfish, especially when compared to notoriously territorial species from the Pao genus. With careful planning, aquarists can maintain them in groups and, in some cases, even with carefully chosen community fish. This quality, together with their striking patterning and lively behaviour, has cemented their reputation as one of the most “aquarium-friendly” pufferfish available.

With proper care, Spotted Congo Puffers are long-lived for their size. In captivity, a realistic lifespan is 8–10 years, with outliers possible beyond that (there are no published, species-specific longevity studies yet; estimates are based on long-term aquarist records and life-history data from closely related freshwater puffers).

A Species Lost to War

For much of the 20th century, T. schoutedeni was known in Europe but remained exceedingly rare in the hobby. The situation worsened dramatically in the mid-1990s, when the First and Second Congo Wars (1996–2003) devastated the Democratic Republic of Congo (DRC). During this period, international exports from the Congo Basin effectively ceased. Transport networks collapsed, collection sites at Pool Malebo and beyond were unsafe, and the country’s infrastructure for wildlife trade was disrupted for over a decade.

As a result, Spotted Congo Puffers became almost mythical among aquarists, known from old literature and anecdotes, but unobtainable in practice. Older hobbyists often recall them as a “lost” species, absent from the trade for nearly two decades.

It was not until 2017–2018 that a handful of exporters in Kinshasa re-established reliable collection operations. By 2018, T. schoutedeni was once again appearing in shipments bound for Europe and North America. Their return sparked immense enthusiasm: here was a small, attractive, and relatively peaceful pufferfish finally available after years of absence.

Today, the species is not only widely traded but also steadily bred and studied by aquarists, ensuring that it is no longer as dependent on sporadic wild collection. Its re-emergence stands as both a reminder of how global events can shape the aquarium trade and a success story of recovery for a once-vanished favourite.

In the wild

The Spotted Congo Puffer (Tetraodon schoutedeni) is native to the lower–middle Congo Basin of Central Africa. Its confirmed distribution is centred on Pool Malebo (formerly Stanley Pool), a broad, lake-like widening of the Congo River between the twin capitals of Kinshasa (Democratic Republic of Congo) and Brazzaville (Republic of Congo).

Historical museum records strongly suggest the species may be effectively restricted to this region, although some reports also note its presence in adjacent tributaries, including the Ubangi and Lua Rivers. The IUCN currently lists T. schoutedeni as Data Deficient, a reflection of how few modern field surveys have been conducted in this part of the Congo Basin.

Pool Malebo spans roughly 450–500 km², stretching 35 km in length and 23 km in width, with depths that fluctuate between 3 and 10 metres depending on seasonal water levels. In the centre lies Mbamu Island, which divides the river’s flow and creates a range of sheltered microhabitats. The pool’s shoreline is ecologically diverse, fringed by marshes, papyrus beds, palm groves, and drifting mats of water hyacinth (Eichhornia).

Seasonal flooding causes the shoreline to advance and retreat by several kilometres, generating a constantly shifting mosaic of habitats. These periodic changes not only reshape available cover but also regulate food availability, dispersing invertebrate populations across the pool’s margins.

Environmental surveys of Pool Malebo describe a warm, soft-water environment with low dissolved mineral content.

Measured parameters include:

Temperature: 26–30 °C
pH: 6.4–7.7
Conductivity: ~30 µS cm⁻¹ (very low, indicating extremely soft water)

This combination of warmth, softness, and seasonal fluctuation is typical of many Congo Basin habitats and has shaped the ecology of T. schoutedeni, which thrives in such conditions.

Spotted Congo Puffers occupy shallow littoral zones where submerged grasses, tree roots, woody debris, and rocky outcrops break up the flow. The substrate is typically sandy or muddy, enriched with silt and organic matter deposited during floods. In these margins, puffers take shelter while scanning for prey, making use of cover both for ambush and for protection from larger predators.

Their feeding is focused on benthic invertebrates, with a strong reliance on small snails, but also including worms, insect larvae, and small crustaceans. The species’ distinctive fused dental plates are perfectly suited to crushing shells, scraping surfaces, and probing into crevices. Observations suggest they are opportunistic hunters, foraging actively throughout the day rather than relying on ambush tactics alone.

Early literature described T. schoutedeni as solitary and aggressive, but this was likely based on limited observations and the challenges of keeping them in small aquaria. Modern aquarium experience, combined with ecological reasoning, suggests the truth is more nuanced.

In Pool Malebo, the species benefits from vast open space, abundant visual barriers, and rich habitat complexity, conditions that diffuse territorial behaviour and allow for loose aggregations. While individuals will still defend feeding patches or resting spots, they appear far more tolerant than many of their relatives, particularly when compared to highly territorial Southeast Asian puffers.

For aquarists, this natural context is significant: it explains why T. schoutedeni can often be kept in small groups in captivity, provided tanks are large, richly structured, and carefully managed to replicate the environmental complexity of their wild habitat.

Conservation & Trade

The conservation status of the Spotted Congo Puffer (Tetraodon schoutedeni) remains uncertain. The species is currently assessed as Data Deficient by the IUCN, reflecting the absence of modern ecological studies and population surveys in its natural range. Its apparent restriction to Pool Malebo and nearby tributaries makes it potentially vulnerable to localised threats, yet there is still no evidence to suggest it is in immediate decline.

Environmental Pressures

Pool Malebo lies adjacent to the rapidly growing cities of Kinshasa and Brazzaville, together home to more than 15 million people. As a result, the system is exposed to a variety of anthropogenic pressures, including:

Water pollution from urban runoff, sewage discharge, and industrial effluents.
Habitat degradation is caused by shoreline development, deforestation, and the expansion of agriculture.
Overfishing, both artisanal and commercial, alters food webs and may reduce populations of invertebrates that the puffer relies on.
Invasive plants such as water hyacinth which form dense mats that reduce oxygen levels and alter littoral habitats.

While T. schoutedeni appears adaptable within its niche, the combined effects of these pressures may pose long-term risks, especially given its limited known distribution.

Sustainability Outlook

Exports from the Congo Basin remain relatively limited compared to more commercially targeted species, and there is currently no evidence of over-collection. However, ongoing habitat degradation around Pool Malebo is a more significant long-term concern. While most specimens available in the trade are still wild-caught, a growing number of aquarists have reported success in breeding this species in captivity.

In the aquarium

The Spotted Congo Puffer has an unusual history in the aquarium hobby. During the 1960s and 70s, it was a familiar sight in the trade, with even the first documented instances of captive spawning taking place during this period. Despite this early promise, there was little appetite to establish long-term breeding programmes, and the fish continued to rely on wild collection.

When the Congo wars of the 1990s and early 2000s brought wildlife exports to a standstill, the species vanished almost entirely. For many aquarists, T. schoutedeni became something of a legend; a fish known from books and stories, but never seen in local shops. It was not until 2018 that reliable exports resumed, sparking a wave of enthusiasm that has only grown since.

Today, although the majority of specimens are still wild-caught from Pool Malebo, there are successful breeding programmes in Germany, Indonesia, and elsewhere, and captive-bred fish are beginning to appear more frequently on the market.

Keeping Spotted Congo Puffers successfully begins with providing them with the right environment. They are active, inquisitive fish that thrive in spacious, mature aquaria, and they should never be kept in cramped conditions.

A single adult requires a tank of around 150 litres (40 US gallons), but they show their best colours and behaviour in much larger aquaria, particularly when maintained in groups.

A heavily structured environment is essential, both to mirror the complexity of their natural habitat and to create a sense of security. When puffers feel exposed, they tend to become shy, stressed, or aggressive, but when they are given an intricate scape, they explore, forage, and display their full range of natural behaviours.

The ideal aquarium for T. schoutedeni combines a soft sandy substrate with plenty of hardscape and vegetation. Driftwood, mangrove roots, and Mopani branches create shaded retreats and natural overhangs, while carefully arranged stones and caves offer secure hiding places.

Among these features, hardy plants can be used to break up open areas and provide cover. Broad-leaved species such as Anubias, Java Fern, Bolbitis, and Amazon swords are particularly well-suited, as they are capable of withstanding the attentions of a pufferfish.

These fish are notorious plant-biters: delicate species such as Tiger Lotus, Crinum calamistratum, and Cryptocoryne balansae are usually shredded within days, and even tougher plants may bear the scars of occasional exploratory bites. With that in mind, aquascaping should favour resilience over delicacy. A tank designed for puffers is rarely a manicured aquascape, but a living, interactive environment where plants and hardscape recover and adapt to the attentions of these intelligent and curious fish.

Water movement should be slow to moderate. In their native Pool Malebo, puffers favour the calmer margins rather than fast-flowing channels, and this preference should be respected in captivity. Strong currents tend to buffet and exhaust them, while gentle circulation encourages steady activity. Filtration is best provided through external canisters fitted with spray bars angled toward the surface, creating a broad, diffuse flow. Many keepers maintain a slightly lowered water level so that returning water splashes down onto the surface, a simple but effective way to promote gas exchange and maintain high levels of dissolved oxygen. Additional circulation pumps can be used if needed, but they must always be fitted with protective guards to prevent inquisitive puffers from becoming trapped.

As with all members of the family Tetraodontidae, T. schoutedeni is highly intolerant of poor water conditions. They produce a considerable amount of waste and require both excellent mechanical filtration and a stable, mature biological filter. Consistently high water quality, combined with good oxygenation, is the foundation of long-term success.

When these conditions are met, the Spotted Congo Puffer rewards its keeper with a lifespan far longer than most small aquarium fish. T. schoutedeni commonly reaches eight to ten years in captivity, and may live even longer under optimal conditions.

Substrate

A soft, sandy substrate is strongly recommended for Spotted Congo Puffers. In their natural habitat at Pool Malebo, the shallow margins are characterised by sandy or muddy bottoms interspersed with vegetation, roots, and woody debris. Replicating this in the aquarium not only provides a natural aesthetic but also supports the fish’s instinctive behaviours.

Spotted Congo Puffers will occasionally engage in wallowing. Individuals settle into the sand, partially embedding themselves as if resting in a shallow hollow. This may serve as camouflage, a stress response, or simply a comfortable resting posture. A soft bed of fine sand allows the fish to do this safely, reducing stress and encouraging natural behaviour.

A different behaviour, reported by several credible keepers, is nose-diving. When startled, T. schoutedeni may dart downwards and strike the substrate headfirst, in the same way that pea puffers (Carinotetraodon travancoricus) and other small puffer species are known to do. It is a sudden, panicked reaction rather than a deliberate foraging behaviour.

A soft, forgiving sand base is therefore critical: it cushions these high-speed impacts and prevents injury to the snout and mouthparts.

For both wallowing and nose-diving, a fine, inert sand substrate is not merely decorative but a welfare requirement. It allows the fish to display natural behaviours while protecting them from harm during startle responses.

Group Sizes

One of the most common questions aquarists ask about the Spotted Congo Puffer is whether they are a shoaling fish. The answer is nuanced. In the wild, Tetraodon schoutedeni is not a true shoaler. Instead, they are best described as loosely gregarious.

In Pool Malebo, individuals are often found in relative proximity, scattered among the submerged grasses, roots, and woody debris along the margins. The sheer scale and complexity of this habitat allow them to coexist without constant conflict: territories overlap, but escape routes are plentiful, and aggression dissipates into the vastness of the pool.

In captivity, however, the limitations of glass boxes make this balance more fragile. Time and again, aquarists have attempted to keep them in pairs or trios, only to watch these small groups unravel as the fish mature. What begins as tolerance often ends with dominance hierarchies hardening, territorial disputes escalating, and one fish being persistently targeted.

Pairs in particular are notoriously unstable, and countless keepers have learned the hard way that what appears harmonious at first almost always breaks down with time.

Because of this, there are really only two sustainable approaches to housing Spotted Congo Puffers. The first is to keep them individually, which avoids the risks of conspecific aggression and allows a single fish to thrive as the centrepiece of its own aquarium. The second is to commit to a larger group of at least six individuals, where aggression is spread across multiple fish rather than concentrated on a single target. In such groups, especially when introduced as juveniles into a richly structured tank, T. schoutedeni displays a more natural, loosely social dynamic that many aquarists find uniquely rewarding.

Sex ratios also matter. Males are more assertive, particularly toward one another, while females are generally more tolerant. For groups, a female-heavy ratio - ideally two females for every male - greatly reduces the risk of serious conflict. Just as important is the way groups are established: puffers introduced simultaneously tend to settle more peacefully, whereas adding new adults into an established group often provokes aggression.

Ultimately, T. schoutedeni are not shoaling fish in the strict sense, but neither are they entirely solitary. They are individualists with a degree of social tolerance that is unusual among pufferfish. To keep them successfully, aquarists must respect this nuance. The safe choices are clear: either keep a single specimen alone, or establish a proper group of six or more in a spacious, well-structured tank. Anything in between is a gamble that, sooner or later, almost always fails.

Tank size

When planning an aquarium for the Spotted Congo Puffer, it is essential to consider not only the total water volume but also the dimensions and footprint. These fish are active, intelligent hunters that spend the majority of their time exploring the lower and middle levels of the tank, weaving between roots, rocks, and plants in search of food.

For a single adult, the minimum recommended footprint is approximately 80 cm x 35 cm (31.5″ x 13.8″), with a water depth of around 40 cm (15.7″). This equates to a volume of about 112 litres (30 US gallons). While it is possible to maintain a specimen in slightly smaller quarters, tanks of this size or larger give the fish enough horizontal space to explore naturally, establish a sense of territory, and avoid feeling confined.

For groups, space becomes dramatically more important. A group of six requires an aquarium at least 120 cm x 45 cm (47″ x 18″) with a water depth of 50 cm (20″). This yields a capacity of roughly 270 litres (71 US gallons), but more important than the number is the footprint: a wide, elongated base allows the fish to spread out, break line of sight, and diffuse aggression.

For groups of T. schoutedeni, it is always better to prioritise length and width over sheer volume. A tall, narrow aquarium may boast impressive litres on paper, but if the base is small, the puffers will be forced into close contact, and conflicts are far more likely.

Aquarists who attempt to keep groups in tall tanks with limited floor space often discover that the extra litres make little difference; the fish remain crowded into the same narrow band of territory, and tensions rise.

For those wishing to house larger groups or to attempt a mixed community, tanks of 150 cm in length or greater are strongly advised. The added horizontal distance provides not just more swimming room but more opportunity for aquascaping with roots, rocks, and plants, which in turn creates the visual barriers and retreat spaces that are essential to long-term harmony. In this sense, aquascaping and tank dimensions are inseparable: a long tank allows for more structure, and more structure means less aggression.

Water values

Maintain the following water parameters:

Temperature: 26–27.5 °C
pH: 6.5–7.5 (middle of range ideal)
General Hardness (GH): 4–10 dGH
Ammonia (NH₃/NH₄⁺): 0 ppm
Nitrite (NO₂⁻): 0 ppm
Nitrate (NO₃⁻): < 15 ppm (as close to zero as possible)

Why these numbers?

These parameters reflect both field data from Pool Malebo, where Spotted Congo Puffers are collected, and the ranges consistently reported in long-term successful husbandry.

Surveys around Kinshasa and Brazzaville record temperatures between 26-30 °C, pH values from 6.4 to 7.7, and very low conductivity averaging just ~30 µS cm⁻¹.

This confirms that the species is naturally adapted to warm, soft, slightly acidic to neutral water. The recommended captive ranges (pH 6.5–7.5 and temperature 26–27.5 °C) sit comfortably within those wild measurements while leaving aquarists a margin of safety for day-to-day variation.

Although Pool Malebo is extremely soft, aiming for a GH of 4–10 dGH in aquaria is a deliberate adjustment. A small amount of hardness provides calcium and magnesium needed for osmoregulation and helps prevent the instability associated with ultra-soft water in closed systems. In practice, this strikes a balance between replicating natural conditions and supporting long-term health.

The expectations of 0 ppm ammonia and nitrite are absolute, as puffers are highly intolerant of nitrogenous waste. The nitrate guideline of <15 ppm is not a hard toxicity threshold but a good-practice benchmark. Chronic exposure to higher nitrate levels has been shown to reduce growth, compromise immune systems, and shorten lifespan in freshwater fishes. In effect, the nitrate target functions as a proxy for system cleanliness: when nitrate is low, it usually means the whole environment is clean, stable, and healthy.

Together, these numbers capture the essence of the Spotted Congo Puffer’s natural habitat while providing the extra stability, buffering, and safety margins that make for reliable, long-term success in the aquarium.

Tankmates

The question of whether the Spotted Congo Puffer can live in a community aquarium has been hotly debated. When the species first reappeared in the trade, many retailers marketed it as the “perfect community puffer,” citing its mild temperament compared to other puffers.

While it is true that Tetraodon schoutedeni is more tolerant than some of its relatives, years of experience among aquarists have shown that this label is misleading. These fish are not mindless killers, but they can be unpredictable. Even well-fed puffers may show unprovoked aggression, either chasing, nipping, or harassing tankmates seemingly at random. For this reason, the Spotted Congo Puffer should never be considered a safe addition to the “typical” community aquarium.

That does not mean tankmates are impossible. With thoughtful planning, biotope-appropriate species can coexist successfully, especially in very large, well-structured aquaria where space and visual barriers diffuse interactions. Matching ecological context is not just a matter of aesthetics; it reflects natural co-occurrence and reduces the risk of mismatched behaviours.

Among the best options are Congo Tetras (Phenacogrammus interruptus), which share the same basin and are readily available in the trade.

Though not short-finned, their size, schooling behaviour, and constant motion make them difficult targets, and they are large enough not to be viewed as prey. Groups of Congo Tetras also add striking colour and activity to the aquarium, creating a vibrant contrast to the puffer’s deliberate movements.

However, Congo Tetras are extremely vigorous feeders and can quickly dominate at mealtimes, leaving puffers struggling to get their share. This does not make them unsuitable, but it does mean the aquarist must put some thought into feeding strategies. Target feeding with tongs, offering sinking foods, or distracting the tetras with floating pellets before feeding the puffers are all effective ways to ensure fair access. With these mitigations in place, the pairing can be very successful.

Other members of the Phenacogrammus genus would be equally suitable, though they are less commonly available outside specialist circles.

Beyond Phenacogrammus, two other groups of African characins are worth highlighting. Alestopetersius species, such as A. smykalai or A. caudalis, are smaller but fast and streamlined, adding shimmering colour and constant activity without overwhelming the puffers or competing too heavily at feeding time. Larger Micralestes, such as M. stormsi or M. acutidens, are sturdy, quick fish with enough size to avoid harassment but still agile enough to evade attention when needed. Like Congo Tetras, they feed enthusiastically, but their activity tends to spread across the midwater column, leaving puffers freer to forage near cover and substrate.

Both Alestopetersius and Micralestes are less common in the trade but make excellent, regionally accurate alternatives when available.

The key with all of these characins, whether Congo Tetras, Alestopetersius, or Micralestes, is to keep them in proper schools of at least eight individuals. Schooling not only keeps their behaviour natural and reduces stress but also prevents puffers from singling out lone fish. The result is a dynamic, visually engaging display: fast-moving characins sweeping the open water while puffers patrol roots and grasses. Tank size is critical here: anything less than 150 cm in length offers too little horizontal room, and in such conditions, aggression is far more likely to become focused and persistent. Attempting community setups in smaller aquaria almost always ends poorly.

Other African fish can also be considered. Kribensis (Pelvicachromis pulcher) are surprisingly effective tankmates in the right-sized aquarium. These small, robust cichlids are territorial in their own right and quick enough to avoid harassment. A breeding pair will often establish a bottom territory and hold it confidently, discouraging puffers from intruding. While not strictly native to the Congo Basin, they share similar ecological niches and water chemistry preferences, making them a sensible and compatible choice for those seeking more behavioural diversity.

Another excellent addition is the Schoutedeni Synodontis (Synodontis schoutedeni), which inhabits Pool Malebo alongside the puffer. This catfish fills a different ecological role, spending much of its time scavenging along the substrate and beneath cover. The fact that both species are named in honour of Henri Schouteden, and both hail from the same waters, makes them a particularly fitting pairing for a faithful biotope aquarium.

It is important to stress that compatibility is never guaranteed. Even with ideal companions, a Spotted Congo Puffer may decide to assert itself, harassing other fish without warning. Any attempt at a community tank should therefore be approached with caution, close observation, and a readiness to separate fish if necessary. And above all, such attempts should only ever be made in very large aquaria, at least 150 cm in length, where space allows tankmates to evade, disperse, and establish their own niches.

For many aquarists, the safest and most rewarding option remains a species-only setup, either as a solitary specimen or in a carefully managed group. But for those willing to take the chance, a biotope-inspired community of puffers can be both authentic and striking; a living snapshot of African river life in the home aquarium.

Sexual dimorphism

Spotted Congo Puffers display clear sexual differences once they reach maturity.

Females are generally the larger sex, often reaching 9–10 cm in length. They develop a broader body, especially around the abdominal region, and appear more rounded even when not carrying eggs. This gives mature females a noticeably heavier, fuller profile compared with males.

Males typically remain slightly smaller, averaging 7–8 cm. Their bodies are slimmer and more streamlined, with a subtle but distinct tapering of the head and snout that creates a more pointed facial profile. When viewed alongside females, males look narrower across the midsection and less bulky overall.

Colour and patterning are not reliable sexing cues, as both sexes share the same spotted markings. The differences in body size and build are the most consistent indicators and become increasingly obvious as the fish mature.

These observations are well established in the aquarium hobby and widely used by experienced keepers and breeders, though it should be noted that no formal scientific study has yet been published comparing male and female morphometrics in T. schoutedeni.

Notable behaviour

One of the great appeals of the Spotted Congo Puffer lies not only in its striking pattern, but in the sheer personality and range of behaviours it displays. These fish are inquisitive, interactive, and often seem to engage with their surroundings in ways that feel almost mammalian. It is this blend of intelligence, charm, and unpredictability that has made them such a favourite among dedicated puffer keepers.

Colour Change & Stress Pattern

Like many puffers, T. schoutedeni is capable of subtle colour change depending on its environment, mood, or health. Well-settled fish typically show a rich golden base scattered with bold dark spots, but shades may lighten or darken throughout the day as they move between rest, activity, or feeding.

Of particular note is their distinctive stress pattern.

When irritated, startled, or otherwise unsettled, the spotted pattern is partially masked by a series of arched dark bars that run across the back, giving the fish a strikingly different appearance. This pattern can appear even under mild stress, such as during water changes or following minor disputes, and it serves as a valuable visual indicator of the fish’s mood. A healthy, content puffer should not display this pattern persistently; its recurrence is a cue to review water quality, tank dynamics, or husbandry.

Eye Retraction

Another fascinating behaviour is the ability to retract the eyes into the head, effectively “rolling them back” when injured, irritated, or even during routine muscular exercise. This is a unique and somewhat startling trait if encountered for the first time. Aquarists may notice their fish practising this movement periodically, apparently to keep the musculature in working order. Brief eye retraction is perfectly normal, but if it is held for long periods, it can signal stress, poor water quality, or harassment from tankmates. As with the stress pattern, it is both a quirk and a useful diagnostic tool for the attentive keeper.

Courtship & Mating Behaviour

The courtship and mating ritual of T. schoutedeni is highly distinctive. During spawning, the male approaches the female and firmly bites onto her underside, clamping near the stomach and hanging on as she swims. He remains attached until she releases eggs, at which point the pair separates. Though the behaviour can appear rough to the observer, it is entirely natural and part of the species’ reproductive strategy. Those who have witnessed and bred the species describe it as a dramatic but reliable sequence, one of the most remarkable displays among freshwater puffers.

Why They’re Beloved

What sets Spotted Congo Puffers apart is the way all these traits combine into a fish that is charismatic and endlessly watchable. They patrol their aquaria with deliberate intent, investigating every crevice and responding with curiosity to activity outside the glass. Their shifting colours, expressive postures, and intelligent eyes make them feel more like pets than ornamental fish.

Many aquarists describe them as “puppy-like,” following their keepers’ movements and recognising feeding cues with surprising speed.

Feeding

One of the greatest joys of keeping Spotted Congo Puffers is watching them eat. These are not fish that simply take food; they hunt it, crunch it, and interact with it in ways that turn every feeding into a performance. Their sharp beaks and deliberate movements are adapted for a very particular diet in the wild, and as keepers, we have the privilege and responsibility of replicating that as closely as possible.

In their natural home, Spotted Congo Puffers are benthic foragers, rooting through sand and vegetation for snails, worms, and aquatic insect larvae. They are specialists in cracking and probing, adapted to extract hidden prey from the silty margins of the Congo River. Bringing this ecology into the aquarium means offering not just food, but variety, texture, and challenge.

At Pufferfish Enthusiasts Worldwide, we encourage keepers to think of feeding as enrichment as much as nutrition. A varied diet provides the broad spectrum of vitamins and minerals needed for healthy growth and long lifespans, but it also keeps puffers mentally stimulated and behaviourally active. Watching a T. schoutedeni methodically crunch through a snail shell or probe the sand for a worm is to see a glimpse of the wild Congo come alive in your aquarium.

Core Foods

The cornerstone of their diet should be snails. Ramshorns, bladder snails, and other soft-shelled species are perfect: they provide the essential dental wear that prevents beak overgrowth, while allowing the fish to express their natural shell-crunching instincts.

Alongside snails, these puffers eagerly take a variety of worms and insect larvae: earthworms, blackworms, bloodworms, mosquito larvae, and phantom midge larvae (glassworms) all make excellent staples. Many aquarists also enjoy supplementing with gut-loaded terrestrial insects such as crickets, small locusts, cockroaches, or woodlice, which the puffers pursue with enthusiasm.

Additional variety can come from small crustaceans such as scuds (amphipods) or planktonic prey like Daphnia and Moina, both of which provide enrichment and encourage active hunting.

Prepared foods should not replace live and frozen staples, but certain high-quality options are accepted by many individuals. Repashy Grub Pie (an insect-based gel food) is widely used, and some puffers will also take insect-based pellets such as Fluval® Bug Bites™. These are especially valuable as backup foods or when live prey is temporarily unavailable.

Suggested Feeding Breakdown

To balance nutrition, dental health, and natural feeding behaviours, the following proportions work well in practice:

50% Snails – ramshorns, bladder snails, and small terrestrial species for essential beak wear
15% Earthworms – chopped red wigglers or small pieces of nightcrawler
10% Insects & Larvae – crickets, cockroaches, woodlice, aphids, mosquito larvae, phantom midge larvae
10% Repashy Gel Foods – especially Grub Pie, which is insect-based and well accepted
10% Insect-Based Pellets – e.g. Fluval® Bug Bites™, used as a supplementary prepared option
5% Variety Mix – blackworms, glassworms, bloodworms, grindal worms, whiteworms, etc.

This balance mirrors their natural ecology while ensuring reliable nutrition and variety in captivity. Snails should form the bulk of the diet to maintain dental health, while worms and insects add protein diversity and stimulate natural hunting behaviour.

More Than Nutrition

Feeding Tetraodon schoutedeni is not simply about keeping them alive; it is about unlocking their natural instincts. Get it right, and every meal becomes an interaction: a fish that recognises you, hunts with purpose, and displays the intelligence and personality that make Spotted Congo Puffers one of the most rewarding species in the freshwater hobby.

Feeding snails

For Spotted Congo Puffers, snails are not optional: they are essential.

Like all puffers, T. schoutedeni has continuously growing dental plates, and without regular access to crunchy, shell-bearing prey, the beak can quickly become overgrown. Left unchecked, this leads to feeding problems that often require veterinary intervention.

The most reliable solution is for keepers to maintain a separate snail culture to provide a constant supply. Breeding aquatic snails is straightforward, and by raising them in mineral-rich water (buffered if necessary), their shells develop to an ideal hardness for both dental wear and safe consumption.

Not all snails are equally suitable. This species shows a clear preference for softer-shelled snails such as Physella acuta (bladder snails), ramshorns, and small cultured terrestrial snails (often sold for reptile or human consumption). These provide the right balance of shell and flesh, encouraging natural feeding without excessive difficulty.

By contrast, trumpet snails (Melanoides tuberculata) and similar species should be avoided. Their shells are too hard for T. schoutedeni to process safely, and repeated attempts can cause injury or lead the puffer to associate snails with pain. They are also relatively poor in flesh compared to softer species.

For long-term success, ensure snails form the cornerstone of the diet, offered regularly and in variety. They are not only vital for dental health but also stimulate the natural hunting and crunching behaviours that make Spotted Congo Puffers so captivating to watch.

Tong Training

One of the most rewarding techniques you can develop with Spotted Congo Puffers is tong training, teaching them to take food directly from feeding tongs. This is more than a convenience; it opens up an entirely new level of interaction between fish and keeper.

Tong training allows you to deliver food precisely where you want it, ensuring that every puffer gets its fair share and that slower individuals are not outcompeted by bolder tankmates. It also makes it easier to provide foods that are unfamiliar to the puffers, which they may be reluctant to accept straight away. Over time, puffers quickly learn to associate the tongs with feeding and will eagerly swim up to meet them.

Beyond practicality, tong training deepens the keeper–fish bond. It transforms feeding time into a moment of trust and engagement, while also giving the keeper close control over diet, portion size, and enrichment.

Click here to read our full Tong Training guide.

Filtration and Tank Maintenance

Spotted Congo Puffers are active hunters with sharp appetites, and groups generate a substantial bioload. Their aquaria must be supported by robust, reliable filtration with both strong biological capacity and effective mechanical polishing.

For most keepers, a large canister filter is the simplest option. Positioning a spray bar along one side maintains circulation and surface agitation, boosting oxygenation. This is critical, as T. schoutedeni comes from well-oxygenated margins of the Congo River system. In larger tanks, a sump is an excellent upgrade, offering high media volume, stable water chemistry, excellent gas exchange, and the flexibility to hide heaters or other equipment out of the display.

No filter, however, can replace good husbandry. Clean, stable water is non-negotiable:

Keep nitrates under 15 ppm, ideally as close to zero as possible.
As a baseline, change at least half the water weekly. Many keepers prefer larger, more frequent changes, especially in densely stocked group tanks or when feeding heavily.
In heavily structured aquascapes with roots, branches, or leaf litter, be mindful of detritus; siphon gently to prevent hidden build-ups.

Why Keep Nitrates Low?

Like many puffers, T. schoutedeni is intolerant of long-term deterioration in water quality. Chronic nitrate exposure in freshwater fishes has been linked to:

Suppressed immune function, leaving fish vulnerable to parasites and bacterial infections
Reduced growth and feed efficiency, limiting their long-term health and vigour
Shortened lifespan and impaired reproductive success

For Spotted Congo Puffers, water quality is not just about survival: it is about enabling them to thrive. When kept in clean, stable, low-nitrate water, they reward their keepers with bold behaviour, natural group dynamics, and the engaging personalities that make this species so adored.

Inflation

Like all puffers, the Spotted Congo Puffer has the remarkable ability to inflate when it feels threatened or highly stressed. By gulping water (or, in emergencies, air), it swells to several times its normal size, making itself harder for predators to swallow and presenting its sharp beak in every direction.

In the aquarium, however, puffing should never be provoked. Forcing a puffer to inflate is extremely stressful and can even be harmful. Inflation is a defence mechanism, not a party trick, and it should only ever happen naturally.

That said, Spotted Congo Puffers also display a quirky behaviour known as “practice puffing.” From time to time, a relaxed fish may casually inflate for a few seconds with no obvious trigger. It is thought this helps them stretch and exercise the muscles involved in inflation. These brief episodes are perfectly normal and not a cause for concern.

If a puffer remains inflated for a prolonged period, however, it is a clear warning that something is wrong. Check for potential stressors such as poor water quality, sudden environmental changes, harassment from tankmates, or external disturbances near the aquarium. Identifying and addressing the underlying cause will allow the fish to settle and deflate naturally.

Inflation is one of the most dramatic and iconic traits of the pufferfish family, but in captivity, it should be seen only rarely and ideally only as the occasional practice puff of a healthy, confident T. schoutedeni.

Toxicity & Toxin Origin

Like many pufferfish, Tetraodon schoutedeni has been reported to contain tetrodotoxin (TTX), a powerful neurotoxin concentrated mainly in the skin, liver, and ovaries. The fish does not produce this toxin itself; rather, it accumulates it through diet in the wild, where certain bacteria and microorganisms associated with their prey are believed to be the source.

The exact toxicity of T. schoutedeni has not been studied in detail, and there is no evidence that it reaches the same levels as some of its larger marine relatives. As with other freshwater puffers, toxin presence is likely to be highly variable depending on origin, season, and diet.

For aquarists, the important takeaway is that this species is not considered dangerous in the aquarium setting. Awareness of its toxin biology is interesting from a scientific perspective, but it has no practical implications for day-to-day care.

Disclaimer

Pufferfish health information given on this site is not intended to act as or replace the advice of a certified veterinary professional. If your pufferfish is experiencing a medical emergency, contact an experienced aquatic veterinarian immediately.