Photo: Xufanc (CC BY-SA 4.0) — via Wikimedia Commons
Mekong Giant Catfish (Pangasianodon gigas)
The largest freshwater fish on the planet — a critically endangered river giant that grows to 3 m and 300 kg, and has absolutely no place in any home aquarium.
Will it live with a Mekong Giant Catfish?
We compare each fish against your mekong giant catfish on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Banjo Catfish✅ CompatiblePeaceful · 15 cm · Medium care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 20–26 °C, workable temperaments, and no predator-and-prey size gap.
- Bearded Corydoras✅ CompatiblePeaceful · 10 cm · Medium care · 18–24 °C (64–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Bearded Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Black Doras Catfish✅ CompatiblePeaceful · 60 cm · Hard care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Bristlenose Pleco✅ CompatiblePeaceful · 12 cm · Easy care · 23–30 °C (73–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Burmese Loach✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Clown Loach✅ CompatiblePeaceful · 30 cm · Medium care · 25–30 °C (77–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Clown Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Common Pleco✅ CompatiblePeaceful · 45 cm · Medium care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Elephant-nose Knifefish✅ CompatiblePeaceful · 35 cm · Hard care · 24–29 °C (75–84 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Giant Kuhli Loach✅ CompatiblePeaceful · 12 cm · Easy care · 24–30 °C (75–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Kuhli Loach✅ CompatiblePeaceful · 10 cm · Easy care · 24–30 °C (75–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Marbled Hoplo✅ CompatiblePeaceful · 14 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Medusa Pleco✅ CompatiblePeaceful · 12 cm · Medium care · 26–30 °C (79–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Porthole Catfish✅ CompatiblePeaceful · 10 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Rubber Lip Pleco✅ CompatiblePeaceful · 12 cm · Easy care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 20–26 °C, workable temperaments, and no predator-and-prey size gap.
- Sailfin Pleco✅ CompatiblePeaceful · 50 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Snowball Pleco✅ CompatiblePeaceful · 16 cm · Medium care · 24–30 °C (75–86 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Spotted Rubbernose Pleco✅ CompatiblePeaceful · 12 cm · Medium care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 20–26 °C, workable temperaments, and no predator-and-prey size gap.
- Spotted Talking Catfish✅ CompatiblePeaceful · 15 cm · Easy care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Striped Eel Loach✅ CompatiblePeaceful · 12 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Upside-down Catfish✅ CompatiblePeaceful · 10 cm · Easy care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Weather Loach✅ CompatiblePeaceful · 25 cm · Easy care · 5–24 °C (41–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Yellow-spotted Pleco✅ CompatiblePeaceful · 35 cm · Medium care · 24–27 °C (75–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Zebra Pleco✅ CompatiblePeaceful · 10 cm · Hard care · 26–30 °C (79–86 °F)
- Compatible on the things that matter: shared water near 26–28 °C, workable temperaments, and no predator-and-prey size gap.
- Bichir⚠️ With cautionSemi-aggressive · 45 cm · Medium care · 24–28 °C (75–82 °F)
- Mekong Giant Catfish and Bichir can both be territorial; doable with space and dense planting, but watch for chasing.
- Black Ghost Knifefish⚠️ With cautionSemi-aggressive · 45 cm · Hard care · 24–28 °C (75–82 °F)
- Mekong Giant Catfish and Black Ghost Knifefish can both be territorial; doable with space and dense planting, but watch for chasing.
- Butter Catfish⚠️ With cautionSemi-aggressive · 45 cm · Medium care · 24–28 °C (75–82 °F)
- Mekong Giant Catfish and Butter Catfish can both be territorial; doable with space and dense planting, but watch for chasing.
- Fire Eel⚠️ With cautionSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Mekong Giant Catfish and Fire Eel can both be territorial; doable with space and dense planting, but watch for chasing.
- Giant Gourami⚠️ With cautionSemi-aggressive · 70 cm · Medium care · 22–28 °C (72–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Golden Sailfin Pleco⚠️ With cautionSemi-aggressive · 45 cm · Medium care · 22–28 °C (72–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Goldfish⚠️ With cautionPeaceful · 30 cm · Medium care · 18–22 °C (64–72 °F)
- Expect Mekong Giant Catfish to harass Goldfish at times; give dense cover and watch them at feeding.
- Imperial Flower Loach⚠️ With cautionSemi-aggressive · 50 cm · Hard care · 15–22 °C (59–72 °F)
- Mekong Giant Catfish and Imperial Flower Loach can both be territorial; doable with space and dense planting, but watch for chasing.
- Koi⚠️ With cautionPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Mekong Giant Catfish clearly outsizes Koi and is semi-aggressive; risky unless the tank is big and well-planted.
- Lima Shovelnose Catfish⚠️ With cautionSemi-aggressive · 50 cm · Hard care · 23–30 °C (73–86 °F)
- Mekong Giant Catfish and Lima Shovelnose Catfish can both be territorial; doable with space and dense planting, but watch for chasing.
- Lyre Tail Pleco⚠️ With cautionSemi-aggressive · 63 cm · Hard care · 21–27 °C (70–81 °F)
- Mekong Giant Catfish and Lyre Tail Pleco can both be territorial; doable with space and dense planting, but watch for chasing.
- Nile Bichir⚠️ With cautionSemi-aggressive · 70 cm · Medium care · 25–28 °C (77–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Orinoco Sailfin Pleco⚠️ With cautionSemi-aggressive · 50 cm · Medium care · 22–28 °C (72–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Royal Pleco⚠️ With cautionSemi-aggressive · 43 cm · Medium care · 23–28 °C (73–82 °F)
- Mekong Giant Catfish and Royal Pleco can both be territorial; doable with space and dense planting, but watch for chasing.
- Spotted Shovelnose Catfish⚠️ With cautionSemi-aggressive · 55 cm · Hard care · 22–28 °C (72–82 °F)
- Mekong Giant Catfish and Spotted Shovelnose Catfish can both be territorial; doable with space and dense planting, but watch for chasing.
- True Parrot Cichlid⚠️ With cautionSemi-aggressive · 33 cm · Hard care · 23–28 °C (73–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Mekong Giant Catfish and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Two assertive fish, one genuinely aggressive: Mekong Giant Catfish and Clown Knifefish will hold territory and clash.
- Mbu Puffer⛔ Not recommendedAggressive · 67 cm · Hard care · 24–28 °C (75–82 °F)
- Two assertive fish, one genuinely aggressive: Mekong Giant Catfish and Mbu Puffer will hold territory and clash.
- Ocellaris Peacock Bass⛔ Not recommendedAggressive · 70 cm · Hard care · 24–30 °C (75–86 °F)
- Two assertive fish, one genuinely aggressive: Mekong Giant Catfish and Ocellaris Peacock Bass will hold territory and clash.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Mekong Giant Catfish and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Mekong Giant Catfish and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Mekong Giant Catfish and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Two assertive fish, one genuinely aggressive: Mekong Giant Catfish and Wolf Cichlid will hold territory and clash.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Mekong Giant Catfish care specs
- Care level
- Hard
- Breeding
- Very Hard
- Max size
- 300 cm (118.1 in)
- Min tank size
- 100000 L (26420.1 gal)
- Temperature
- 20–28 °C (68–82 °F)
- pH
- 6.5–7.5
- Hardness
- 2–30 dGH
- Lifespan
- 20–60 years
- Diet
- Herbivore
- Swim level
- Middle
- Group size
- Best alone or in a pair
- Family
- Pangasiidae
- Origin
- Mekong River basin — Thailand, Laos, Cambodia, Vietnam, southern China
What is a Mekong giant catfish?
The Mekong giant catfish (Pangasianodon gigas) holds a superlative that few freshwater animals can match: it is widely recognised as the largest strictly freshwater fish on Earth. Adults commonly exceed 2 m (6.5 ft) and 150 kg (330 lb); the record specimen, caught in Thailand in 2006, measured 2.7 m and weighed 293 kg (646 lb). A maximum size of 300 cm (nearly 10 ft) is documented in the literature. Despite that bulk it is a dedicated herbivore — toothless, nearly barbel-free, and grey-to-white in colour with a pale belly, lacking the bold stripes of its smaller pangasiid relatives.
This is not an aquarium fish. It is included in this database as a reference species for fishkeepers who encounter it in the wild, in conservation media, or who are searching for information after seeing it listed in a store that should know better. The care profile below reflects what is understood from field research and the very few institutional holding programmes that have attempted to keep juveniles.
Where do Mekong giant catfish come from?
Pangasianodon gigas is endemic to the Mekong River basin — a drainage that runs through southern China, Myanmar, Thailand, Laos, Cambodia, and Vietnam, covering roughly 800,000 km². The species undertakes long seasonal migrations, moving upstream into cooler highland reaches to spawn and returning downstream as water levels fall. The water it inhabits is soft to moderately hard (2–30 dGH), neutral to slightly acidic (pH 6.5–7.5), and varies seasonally in temperature from around 20 °C (68 °F) in cooler upland stretches to 28 °C (82 °F) in the lowland wet season.
Wild populations are now so depleted — perhaps only a few hundred individuals remain — that sightings of juveniles in the main river channel are exceptionally rare. Most of what we know about the species’ behaviour comes from the brief period when it was caught commercially, from Thai government hatchery programmes, and from IUCN field surveys.
What size tank does a Mekong giant catfish need?
100,000 litres (26,400 gallons) is the documented minimum used in the scientific and husbandry literature for juveniles, and even that figure is contested as inadequate for long-term adult care. Adults patrolling the Mekong cover dozens of kilometres daily; no manmade enclosure replicates that. Public aquariums that have trialled juvenile specimens typically report severe welfare problems — wall-strike injuries, chronic stress, and stunted development — even in very large displays.
In practical terms: this fish cannot be kept in private hands anywhere in the world, both because no feasible tank exists and because CITES Appendix I listing makes acquisition and transfer across international borders illegal without extraordinary institutional permits.
What water parameters do Mekong giant catfish need?
Field data and hatchery records indicate the following ranges:
- Temperature: 20–28 °C (68–82 °F) — the species tolerates a broader range than most tropicals and actually prefers the cooler end during upstream spawning migrations.
- pH: 6.5–7.5, leaning neutral.
- Hardness: 2–30 dGH — tolerant of a wide range from very soft highland water to moderately hard lowland reaches.
The broad tolerances reflect the fish’s wide migratory range rather than adaptability to confined conditions. Water quality in institutional holding programmes must be pristine: the sheer bioload of a large specimen is extreme, and ammonia accumulation in any realistic enclosure is a persistent challenge.
What do Mekong giant catfish eat?
Uniquely among large catfish, Pangasianodon gigas is a strict herbivore as an adult. Juveniles are thought to consume small invertebrates and plankton, but individuals longer than roughly 1.5 m rely almost entirely on periphyton — the algae, biofilm and detritus that coats submerged rocks and woody debris in the river. The species has no teeth in adulthood, having lost them as it transitioned to a grazing lifestyle.
In Thai hatchery programmes, captive juveniles have been maintained on aquatic plants, algae wafers, spirulina-based feeds, and softened plant matter, but long-term nutritional success beyond the first couple of years has not been well documented. The gut is proportionally long, consistent with a low-calorie, high-bulk herbivorous diet.
Are Mekong giant catfish aggressive — and what fish can live with them?
The species is classified here as semi-aggressive based on hatchery observations and the behaviour typical of very large catfish in confined space: individuals compete aggressively for territory and food when density is high, and a panicked 200 kg fish in a tank is a danger both to itself and to anything else in the water. In the wild, adults are generally described as non-predatory toward other fish — they have no teeth and no mechanism for prey capture — but their sheer mass makes them incompatible tankmates for virtually any other species.
See Mekong giant catfish tank mates for a fuller discussion, though compatibility in any realistic captive context is essentially moot. If you are looking for a large, manageable pangasiid for a home aquarium, the iridescent shark (Pangasionodon hypophthalmus) is the hobby-available relative — itself a species that typically reaches 90–100 cm (3 ft) and outgrows most home setups.
How do you tell male and female Mekong giant catfish apart?
Sexual dimorphism in this species is subtle and primarily visible in mature adults. Gravid females develop a noticeably rounder, fuller abdomen as the ovaries enlarge in pre-spawn condition; males are typically slimmer through the body. There are no external differences in fin shape, colouration, or head morphology that reliably distinguish the sexes at a distance, which complicates management in the Thai government’s captive breeding programme. Ultrasound imaging has been used to confirm sex in hatchery fish.
How do Mekong giant catfish breed?
Breeding is rated very hard — a designation that barely captures the logistical reality. In the wild the species is a long-distance migratory spawner, travelling hundreds of kilometres upstream in the Mekong to spawn in the cooler, fast-flowing upper reaches, likely in what is now southern China. The exact spawning sites have never been conclusively identified. No confirmed captive-bred generation has been raised entirely in artificial conditions; the Thai Department of Fisheries’ conservation programme relies on hormone-induced stripping of wild-caught broodstock to produce fry for restocking.
Spawning triggers appear to include seasonal temperature drop, changes in flow and barometric pressure, and the migratory journey itself — cues that cannot be replicated in any captive setting. Fry are raised on plankton and gradually transitioned to plant-based feeds.
What are common Mekong giant catfish diseases?
The health challenges documented in institutional settings largely arise from the stress of confinement rather than species-specific pathogens:
- Physical trauma — large catfish in confined tanks frequently injure themselves on walls and equipment; blunt-force injuries become infection entry points.
- Bacterial infections — secondary infections from wound sites (Aeromonas, Pseudomonas and related bacteria are common opportunists in stressed catfish).
- Parasitic infestations — skin and gill flukes (Gyrodactylus, Dactylogyrus spp.) are reported in hatchery-held pangasiids; wild fish carry their own parasite fauna that may amplify under crowding.
- Nutritional deficiencies — maintaining the correct herbivore diet long-term in captivity is difficult; vitamin and mineral imbalances have been noted in hatchery juveniles.
Prevention centres on eliminating confinement stress, maintaining exceptional water quality, and providing a nutritionally complete plant-based diet. These measures are practically achievable only at an institutional scale.
Health note: Diagnosis and treatment protocols for large, critically endangered fish are highly specialised. Consult a veterinarian with large-fish or aquatic-animal experience, and confirm any symptoms against peer-reviewed sources before intervening.
How long do Mekong giant catfish live?
Lifespan estimates range from 20 to 60 years, though the upper end is inferred rather than directly observed — age determination in this species relies on growth-ring analysis of skeletal material, and very few wild fish have been available for study. The species’ growth rate is extraordinary for a freshwater fish: individuals can gain 200 kg within their first six years under good conditions. Long-lived wild specimens likely reach their maximum size of 300 cm (10 ft) only after several decades in undisturbed river habitat. Even in hatchery programmes, fish that survive into adulthood are considered conservation assets rather than candidates for long-term captive maintenance.
Frequently asked questions
Can you keep a Mekong giant catfish in a home aquarium?
No. This species reaches 3 m and over 300 kg and is one of the most active, wide-ranging freshwater fish on Earth. It is critically endangered, its international trade is banned under CITES Appendix I, and it is totally unsuitable for any private tank. Even public aquariums rarely attempt to house adults.
Why is the Mekong giant catfish endangered?
Overfishing, dam construction, and loss of spawning habitat along the Mekong River have driven populations to the brink. Basin-wide catches collapsed from roughly 70 fish per year in 1990 to fewer than 10 in recent years. It now sits on the IUCN Red List as Critically Endangered.
What you need to keep a mekong giant catfish
The baseline is a heated, filtered 100000 L+ tank: a reliable heater to hold 20–28 °C (68–82 °F), a gentle filter that won't batter a mekong giant catfish in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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