Pires's Driftwood Catfish

Quick summary

Tocantinsia piresi is a huge and very rarely imported driftwood catfish from the major river systems of the eastern Brazilian Amazon. Published records reach 51.5 cm total length and approximately 2 kg. This is not a pleco, an algae eater, or a normal community catfish – it is suitable only for advanced keepers with public-aquarium-scale housing of at least 1,000 litres. Its natural diet is unusual too: fruit and seeds dominate during high water, while fish and insects become more important as levels fall.

🐠 Build a tank around this species

In this guide:

• Introduction
• Quick Stats
• Appearance
• Natural habitat
• Tank size and setup
• Water parameters
• Filtration and equipment
• Diet and feeding
• Behaviour and temperament
• Tank mates
• Breeding
• Common diseases and health
• Frequently asked questions
• Related guides

Introduction

Tocantinsia piresi is one of the most substantial members of the driftwood catfish family Auchenipteridae. It has a broad, flattened head, an exceptionally capacious mouth, and a deep, muscular body suited to life in large tropical rivers.

The genus Tocantinsia contains only this one accepted species. The fish was originally described as Glanidium piresi by Miranda Ribeiro in 1920. A second description, Tocantinsia depressa (Mees, 1974), was later found to be the same fish and placed in synonymy, though the genus name Tocantinsia itself remained valid.

English aquarium literature does not provide a firmly established common name, which makes the scientific name the safest display title. “Pires’s Driftwood Catfish” is a useful descriptive name, while Brazilian sources record local names including pocomao, boca-de-sapato, capadinho and anojado. The species name honours Antenor Pires, a taxidermist on the expedition that collected the original specimen.

This is not simply an oversized version of a small woodcat, and older summaries describing it as a small fish (some give a maximum of only 10 cm) are contradicted by every specialist and field source – dedicated catfish references explicitly warn against this outdated figure, and detailed field studies from the Xingu River document animals up to 51.5 cm total length. Wild research shows a strong relationship with the annual flood pulse: the fish feeds heavily on terrestrial fruit and seeds when flooded habitat becomes accessible, shelters among riverbed rocks during lower water, and shifts its diet towards aquatic insects and fish as levels fall. Its reproductive cycle is seasonal too, peaking during low water rather than during the flood.

Appearance

Tocantinsia piresi has a robust, somewhat compressed body with a broad, dorsally flattened head. Its mouth gape is extremely wide, reaching back to roughly the level of the eye – a feature that may explain the Brazilian name boca-de-sapato, meaning “shoe mouth.” Several pairs of sensory barbels surround the mouth.

The dorsal and pectoral fins are supported by strong spines. The adipose fin is comparatively small, and the caudal fin is distinctly forked. Colouration is generally understated and variable – the upper body may be olive-brown, grey-brown or tan, becoming paler underneath, with irregular darker mottling breaking up the outline. Like other catfish, its skin lacks conventional body scales.

Juveniles may show more obvious patterning, while large adults become increasingly heavy-bodied and broad-headed. Photographs can make the fish appear much smaller than it really is – a documented 51.5 cm animal and research specimens approaching 2 kg are comparable in bulk to sizeable food fish rather than ordinary aquarium catfish.

Males and females cannot reliably be separated by general colour. In a Xingu field study, males were slightly heavier on average, but the sexes overlapped considerably in body size. As with other auchenipterid catfish, mature males may develop reproductive modifications to the anal fin, but immature imported fish should not be sexed confidently from photographs alone. The clearest published information concerns maturity size: females reached an estimated 50% maturity at 33.76 cm standard length, males at 34.84 cm.

Natural habitat

Older summaries sometimes restrict this species to the upper Tocantins River alone. Verified records and modern ecological studies support a broader eastern Amazon distribution, including the Tocantins-Araguaia system, the Xingu (including the middle Volta Grande region), and the Tapajos/Teles Pires system – the type specimen itself came from the Rio Sao Manoel, now known as the Teles Pires.

The Xingu is a large clearwater tributary with relatively low pH, conductivity and suspended-solid levels. Ecological research found the species shelters in burrows and spaces among riverbed rocks during the dry season; juveniles have been reported from deeper sections of large river channels during low water. As water rises, flooded margins provide access to fruit, seeds and other terrestrial food. This is primarily a large-river and flood-pulse fish rather than a small forest-creek specialist.

An aquarium cannot reproduce an entire floodplain ecosystem, but it can provide the fundamentals: enormous open-water volume, shaded rock or wood refuges, clean oxygenated water, and enough space for the fish to turn without contacting the glass or decorations. Smooth, stable boulders and substantial driftwood can create shelter, though every structure must be secured, since a large adult may shift loose objects. Fine sand is safer than sharp gravel around the belly and sensitive barbels.

Tank size and setup

The adult aquarium must be planned before purchasing this species. Tankora’s recommended working minimum is 1,000 litres with a footprint of at least 250 x 80 cm – greater width and volume are strongly preferable. Length alone is not enough: the fish must be able to turn comfortably, travel between shelters, and escape the visual pressure of other large fish.

A smaller juvenile aquarium may work only as a temporary grow-out system – the permanent adult accommodation should already be available, or realistically funded, before the fish is purchased.

Provide at least one deep, dark refuge large enough for the adult to enter without scraping its dorsal or pectoral spines. Wide rock overhangs, oversized inert pipes, and exceptionally robust driftwood arrangements are more appropriate than ordinary catfish caves. Leave a broad open corridor for swimming and feeding, protect heaters and filter intakes, and use a strong, securely fitted lid, since large catfish can displace loose covers when startled.

One specimen is the sensible default. No evidence exists that this species requires a group in captivity, and every additional adult dramatically increases the necessary space, filtration and number of shelters. Multiple specimens should only be considered in an exceptionally large specialist installation – never use overcrowding to suppress aggression, and don’t assume compatible juveniles will remain compatible as adults.

Water parameters

Reliable species-specific aquarium parameter data are limited and sometimes contradictory, so the ranges above should be treated as practical working values rather than documented natural limits. Stable chemistry, high dissolved oxygen and excellent waste control matter more than hitting one exact figure. Ask the supplier about the conditions the individual was held in, and acclimate gradually.

Ammonia and nitrite must remain undetectable. Control nitrate through high-capacity filtration, measured feeding and regular partial water changes – a 50 cm, kilogram-scale omnivore produces substantial waste, particularly after protein-rich meals. Replacement water should be closely matched for temperature and mineral content; sudden chemistry changes can be more harmful than a stable value toward one end of the range.

The Xingu study location is clearwater, so there is no justification for forcing extremely dark or highly acidic blackwater conditions. Driftwood and botanicals can be used for shelter and enrichment if they don’t obstruct swimming or destabilise water quality – brown water should never be assumed to be soft, acidic or clean without testing.

Filtration and equipment

Use mature, redundant filtration capable of processing the waste produced by a very large catfish – a substantial external canister system, sump, or equivalent high-capacity biological filter is appropriate, with mechanical stages that can be serviced regularly without dismantling the whole system.

Provide broad circulation and strong surface movement while retaining calmer water inside the fish’s shelters. There is no scientifically established species-specific turnover figure; assess filtration performance through oxygenation and measured waste levels rather than the manufacturer’s volume rating alone.

Screen pump intakes and position outlets so the fish cannot become trapped behind equipment. Use protected heaters, or heat the filter system externally where practical – a strong adult may break an exposed glass heater. A secure lid, reliable thermometer and proper water-testing equipment are fundamental. Subdued lighting will encourage the fish to emerge; a low-output red observation light can allow monitoring after dark without disturbing it.

Diet and feeding

Tocantinsia piresi is a seasonal omnivore with a pronounced frugivorous bias during high water. A 2022 Xingu study examining 584 stomachs found fruit and seeds dominated the diet overall; during one falling-water period aquatic insects became the principal food, while the limited dry-season sample contained fish, aquatic insects and terrestrial insects. It should not be described as a strict predator, even though it possesses a large mouth and is capable of consuming smaller fish.

In captivity, build its diet around quality sinking omnivore pellets or gel foods, supplemented with suitable plant material and whole invertebrate foods. Possible foods include softened peas, courgette, squash, small amounts of suitable low-acid fruit, earthworms, mussel, shrimp, insect larvae and occasional fish-based foods. Remove uneaten food promptly – wild fruit consumption doesn’t justify sugary human food, excessive fruit quantities, or a fully vegetarian diet.

Feed after dusk, or position food near the shelter once the fish is established. Juveniles may accept measured daily meals; large adults generally need smaller portions relative to body weight and may not need heavy feeding every day. Monitor condition from above and the side – repeated rich feeding can cause obesity and severe water-quality deterioration, and a secretive fish may lose weight unnoticed if faster tankmates consume its food first.

Behaviour and temperament

Tocantinsia piresi is secretive and strongly associated with shelters. Imported specimens are reported to hide for extended periods, consistent with field observations of the species occupying spaces and burrows among riverbed rocks during low water. Provide an appropriate refuge from the fish’s first day, and expect most activity around dusk, darkness and feeding time.

Hiding during daylight is not necessarily a sign of illness, though rapid breathing, declining body mass, damaged skin, abnormal posture or continued food refusal warrants investigation. The species is more accurately described as a large opportunistic omnivore than a deliberately aggressive hunter, but its enormous mouth, powerful body and fin spines make careless mixing hazardous – it may swallow small fish and can injure or be injured by territorial tankmates.

Soft mesh nets are inappropriate, since the dorsal and pectoral spines may become entangled. Move the fish using a large rigid submerged container or a strong fish bag – handling a full-grown specimen may require professional assistance.

Tank mates

A single-species display is the lowest-risk recommendation. In a genuinely enormous aquarium, possible companions would need to be robust, non-nipping fish too large to swallow and capable of sharing warm, clean, moderately moving water, and even then, provide separate retreats and monitor feeding carefully. Compatibility cannot be guaranteed by a simple species list; individual size, temperament, shelter ownership and the aquarium’s actual footprint all affect the outcome.

Good tank mates

• None recommended as a default – a single-species display is the safest approach, given this fish’s adult size and opportunistic predatory diet.

Fish to avoid

• Neon Tetra – small enough to be swallowed whole.
• Guppy – small enough to be swallowed whole.
• Cockatoo Dwarf Cichlid – small enough to fit inside this catfish’s mouth.
• Discus – a slow, delicate feeder that would lose out to a large opportunistic omnivore.
• Tiger Barb – a fin-nipper that could target this fish’s sensitive barbels.
• Oscar – large and aggressive enough to risk real conflict with a fish this size.
• Jaguar Cichlid – highly predatory and territorial, a genuine conflict risk.
• Common Pleco – large enough to compete aggressively for cover.
• Sailfin Pleco – another large, competitive bottom-dweller and potential shelter rival.
• Juvenile fish of any species – size alone is not a reliable safety margin as this catfish grows.

An apparently peaceful juvenile community should never be treated as evidence of permanent adult compatibility.

Breeding

No repeatable captive-breeding method for Tocantinsia piresi has been documented. The strongest evidence comes from 897 wild specimens sampled in the middle Xingu between 2012 and 2014: females reached an estimated 50% sexual maturity at 33.76 cm standard length, males at approximately 34.84 cm. Gonadal activity in both sexes was strongest during low water and continued at a lower level into the rising-water period, with researchers concluding that spawning appears to occur principally during the dry season – differing from the flood-season reproductive timing documented for the smaller Auchenipterus nuchalis examined in the same study.

Recreating the natural cycle in captivity would require several mature fish, an enormous aquarium system, seasonal changes in water level and food availability, and detailed observation without disturbing shelter use. Auchenipterid catfish possess specialised reproductive anatomy, and internal insemination occurs within the family, but Tankora will not present a species-specific courtship sequence, incubation period or parental-care strategy for this species without direct evidence.

Anyone attempting a legitimate breeding project should maintain detailed provenance records, avoid mixing fish from different river systems, and document collection/supplier information, sex characteristics, water temperature, conductivity, water-level changes, feeding changes, and any courtship, spawning or developmental observations. Given the fish’s adult size and specialist requirements, a serious breeding project belongs in an institutional or unusually large specialist facility rather than a typical home aquarium.

Common diseases and health

No aquarium disease is known to be unique to Tocantinsia piresi. The principal preventable risks are poor water quality, low dissolved oxygen, obesity, injuries from unstable decorations, abrasion during capture, aggression from tankmates, and pathogens introduced with new fish or live food. Quarantine new arrivals in a suitably large, fully filtered system, and monitor respiration, body condition, skin, barbels and feeding response – its hidden lifestyle makes scheduled health checks particularly important.

Take care when medicating a scaleless catfish. Do not automatically halve every dose, add salt, raise temperature, or combine several treatments – correct treatment depends on diagnosis, active ingredient, manufacturer instructions, water chemistry and available tolerance information. Test ammonia, nitrite, oxygen and temperature before assuming unusual behaviour is caused by infection, and consult an aquatic veterinarian or experienced fish-health professional when symptoms are severe, persistent, or affecting several fish.

The dorsal and pectoral spines can puncture skin and cause a painful wound. Avoid restraining the fish with bare hands, and never lift a large specimen in a soft mesh net. If a person is punctured, clean the injury promptly and seek medical advice for severe pain, swelling, retained spine material or signs of infection – though this handling warning should not be exaggerated into a claim that the species is dangerously venomous.

Frequently asked questions

How large does Tocantinsia piresi grow?

A published Xingu dataset records a maximum of 51.5 cm total length and approximately 2 kg. Other research samples included fish up to 46 cm standard length, so it must be planned for as a very large catfish – older reports describing it as a small species are outdated and contradicted by specialist and field sources.

Is Tocantinsia piresi a pleco or algae eater?

No. It is a driftwood catfish belonging to Auchenipteridae. Wild fish are seasonal omnivores: fruit and seeds dominate during high water, while aquatic insects and fish become more important as water levels fall.

What tank size does Tocantinsia piresi need?

An adult requires specialist accommodation of around 250 cm long and approximately 1,000 litres or more, with a very wide footprint. Smaller juvenile accommodation is temporary and must not be treated as the adult minimum.

Can Tocantinsia piresi live with smaller fish?

Small fish should not be considered safe. Although plant material is an important part of its natural diet, this catfish also consumes fish and aquatic insects and has an exceptionally wide mouth.

Has Tocantinsia piresi been bred in aquariums?

No repeatable captive-breeding method has been documented. Wild Xingu fish mature at approximately 34 cm standard length, with reproductive activity peaking mainly during low water.

Related guides

• Colombian Wood Catfish Care Guide – another large, secretive driftwood catfish from the same family.
• Giant Bumblebee Catfish Care Guide – another large, rarely-kept South American catfish for specialist setups.