Photo: O. Schneider (CC BY-SA 3.0) — via Wikimedia Commons
Amazon Puffer (Colomesus asellus)
The only puffer that genuinely plays well with others — a hyperactive, shoaling, fully freshwater puffer from the Amazon basin.
Will it live with a Amazon Puffer?
We compare each fish against your amazon puffer on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Ash Lipped Apisto✅ CompatibleSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Banded Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Black Kuhli Loach✅ CompatiblePeaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra✅ CompatibleSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bolivian Ram✅ CompatiblePeaceful · 8 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.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Bright Diamond Tetra✅ CompatiblePeaceful · 7 cm · Hard 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.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
- Brilliant Rasbora✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Brilliant Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Buenos Aires Tetra✅ CompatibleSemi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Burmese Loach✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Celebes Rainbowfish✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Clown Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Congo Tetra✅ CompatiblePeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Costa's Tetra✅ CompatiblePeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
- Croaking Gourami✅ CompatiblePeaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Glass Catfish✅ CompatiblePeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Gold Barb✅ CompatiblePeaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
- Hongsloi Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Leopard Frog Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 25–30 °C (77–86 °F)
- Both are peaceful, and their water overlaps around 25–28 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Pantanal Corydoras✅ CompatiblePeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Pantanal Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Scissortail Rasbora✅ CompatiblePeaceful · 8 cm · Easy care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Scissortail Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Silver Tetra✅ CompatiblePeaceful · 9 cm · Easy 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.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Silver Tetra in a shoal of 6+ or it gets stressed and nippy.
- Splashing Tetra✅ CompatiblePeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Splashing Tetra in a shoal of 6+ or it gets stressed and nippy.
- Thick-lipped Gourami✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Zebra Loach✅ CompatiblePeaceful · 9 cm · Medium care · 23–26 °C (73–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Afra Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 24–28 °C (75–82 °F)
- Different pH ranges (6.5–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Afra Cichlid and Amazon Puffer are close in size, but the semi-aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Your 120 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Afra Cichlid in a shoal of 6+ or it gets stressed and nippy.
- African Butterfly Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- African Butterfly Cichlid and Amazon Puffer are close in size, but the semi-aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Dwarf Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–30 °C (75–86 °F)
- Expect Agassiz's Dwarf Cichlid to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Badis⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Badis and Amazon Puffer are close in size, but the semi-aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Bamboo Shrimp⚠️ With cautionPeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Amazon Puffer may eat Bamboo Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Bandit Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 22–26 °C (72–79 °F)
- Bandit Cichlid and Amazon Puffer are close in size, but the semi-aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Your 120 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Bandit Cichlid in a shoal of 6+ or it gets stressed and nippy.
- Brichardi Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Different pH ranges (6.5–7.5 vs 7.8–9); doable if you sit in the shared band, but not ideal long-term.
- Expect Brichardi Cichlid to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Cockatoo Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Cockatoo Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Convict Cichlid⚠️ With cautionAggressive · 10 cm · Easy care · 21–28 °C (70–82 °F)
- Convict Cichlid and Amazon Puffer are close in size, but the aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Daffodil Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 23–27 °C (73–81 °F)
- pH preferences only just meet (Amazon Puffer 6.5–7.5 vs Daffodil Cichlid 7.8–9) — target the overlap and acclimate slowly.
- Daffodil Cichlid is semi-aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Demasoni Cichlid⚠️ With cautionAggressive · 9 cm · Hard care · 23–27 °C (73–81 °F)
- Different pH ranges (6.5–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Demasoni Cichlid is aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Your 120 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Demasoni Cichlid in a shoal of 12+ or it gets stressed and nippy.
- Dwarf Gourami⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Dwarf Gourami to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Electric Yellow Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 23–26 °C (73–79 °F)
- Different pH ranges (6.5–7.5 vs 7.8–8.9); doable if you sit in the shared band, but not ideal long-term.
- Expect Electric Yellow Cichlid to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Goldeneye Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Easy care · 24–28 °C (75–82 °F)
- Expect Goldeneye Dwarf Cichlid to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Lifalili Jewel Cichlid⚠️ With cautionAggressive · 9 cm · Medium care · 22–28 °C (72–82 °F)
- Lifalili Jewel Cichlid is aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Mexican Tetra⚠️ With cautionSemi-aggressive · 9 cm · Easy care · 18–25 °C (64–77 °F)
- Mexican Tetra and Amazon Puffer are close in size, but the semi-aggressive one tends to dominate — add amazon puffer in a group to spread the pressure.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Keep Mexican Tetra in a shoal of 6+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Alligator Gar (250 cm) is big enough to swallow the 8 cm Amazon Puffer whole.
- Alligator Gar clearly outsizes Amazon Puffer and is aggressive; risky unless the tank is big and well-planted.
- Your 120 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Amazon Puffer is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
- Expect Clown Knifefish to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Fire Eel (100 cm) is big enough to swallow the 8 cm Amazon Puffer whole.
- Expect Fire Eel to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Koi (90 cm) is big enough to swallow the 8 cm Amazon Puffer whole.
- Your 120 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Amazon Puffer is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Redtail Catfish is aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Your 120 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Spotted Gar (90 cm) is big enough to swallow the 8 cm Amazon Puffer whole.
- Spotted Gar clearly outsizes Amazon Puffer and is aggressive; risky unless the tank is big and well-planted.
- Your 120 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Wels Catfish (300 cm) is big enough to swallow the 8 cm Amazon Puffer whole.
- Expect Wels Catfish to harass Amazon Puffer at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Size gap is too large (72 vs 8 cm): Wolf Cichlid will treat Amazon Puffer as food.
- Wolf Cichlid is aggressive and may chase or nip the smaller Amazon Puffer — plant heavily and break up sight lines.
- Your 120 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
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.
Amazon Puffer care specs
- Care level
- Medium
- Breeding
- Very Hard
- Max size
- 8 cm (3.1 in)
- Min tank size
- 120 L (31.7 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 6.5–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 5–10 years
- Diet
- Carnivore
- Swim level
- All
- Group size
- 6+ (shoaling)
- Family
- Tetraodontidae
- Origin
- South America — Amazon and Orinoco river basins (Brazil, Peru, Colombia)
What is an Amazon Puffer?
The Amazon puffer (Colomesus asellus) is the most sociable freshwater puffer available to hobbyists. While virtually every other puffer species is solitary and aggressive, C. asellus is genuinely peaceful with its own kind and with most community fish, and it actively suffers when kept without companions. Kept in a group of six or more, the species is engaging, highly active and full of personality; kept alone, it becomes stressed and prone to disease.
Adults reach around 8 cm (3 in). The body is a pale yellow-green with bold dark brown or black banding across the dorsal surface and a pale, rounded belly. The species is distributed across the Amazon and Orinoco river basins in Brazil, Peru and Colombia and is entirely freshwater throughout its life — no brackish acclimation is needed or wanted.
Where do Amazon Puffers come from?
Wild Colomesus asellus inhabit broad, fast-moving floodplain rivers and flooded forest channels of the Amazon and Orinoco systems. These rivers are warm, soft and slightly acidic, with tannin-stained water, sandy substrate and driftwood. The species is rheophilic — it naturally lives in areas with meaningful current — which directly informs the filtration and flow rate it needs in captivity.
Most fish in the trade are wild-caught rather than captive-bred. Acclimation to captive conditions takes patience, and pristine water quality from the start is non-negotiable.
What tank size and setup do Amazon Puffers need?
The minimum tank for a group of six — the smallest recommended group — is 120 litres (30 gallons), and a longer footprint is far more valuable than height. Amazon puffers cruise continuously across the full water column, so a 90–120 cm long tank gives them room to move. Larger groups, or the addition of tank-mates, push the requirement upward quickly; a 200 L (55 gal) setup is a much more comfortable long-term choice.
Filtration should be robust. A canister filter or two internal filters positioned to create a gentle lengthwise current replicates the flow these fish expect. They are sensitive to ammonia and nitrite, so the tank must be fully cycled before any puffers are introduced, and regular water changes of 25–30% weekly are important to keep nitrates in check.
For decor, use sand substrate, driftwood and smooth river stones with areas of open swimming space. Live plants are a welcome addition — Amazon sword, vallisneria and Java fern all suit the parameters — but dense planting is less critical than for timid species, since these fish are bold and active.
What water parameters do Amazon Puffers need?
- Temperature: 23–28 °C (73–82 °F). A reliable heater is essential.
- pH: 6.5–7.5 — soft to neutral, mirroring Amazonian conditions.
- Hardness: 2–12 dGH. Softer water is preferred; hard tap water should be cut with RO or collected rainwater if hardness regularly exceeds 12 dGH.
Stability is more important than precision. Sudden parameter swings stress puffers and open the door to disease. Test water weekly when the tank is new, and continue monthly testing once it is established. Because wild-caught fish may take time to settle, keep conditions on the softer, slightly acidic end of the range during the initial acclimation period.
What do Amazon Puffers eat?
Amazon puffers are carnivores with a critical dietary requirement: hard-shelled food to wear down their ever-growing beak plates. The fused dental plates grow continuously, and if they are not abraded by crunching hard prey, the beak overgrows to the point where the fish can no longer feed — a painful and fatal outcome that is entirely preventable.
Offer small live or frozen bladder snails, ramshorn snails or assassin snail juveniles two or three times per week as the beak-maintenance staple. Supplement with frozen bloodworms, daphnia, brine shrimp and small pieces of clam or mussel meat. Variety keeps the fish in condition and prevents nutritional gaps. Feed once or twice daily in amounts consumed within two to three minutes, and remove uneaten food promptly to protect water quality.
Dry pellets or flake are typically refused. Do not rely on them as a primary food source; these are obligate wet-food carnivores in practice.
How do Amazon Puffers behave — and what fish can live with them?
Colomesus asellus is one of the few puffer species that can genuinely be called peaceful. It does not attack other fish unprovoked, it is non-territorial and it actively prefers to shoal with its own kind — keeping fewer than six results in visible stress. Within the group, individuals establish loose social hierarchies but there is rarely serious aggression.
The caveat is opportunistic fin-nipping. Long, slow-moving fins are a temptation, so avoid tank-mates such as bettas, fancy guppies, angelfish or any species with elaborate finnage. Good companion choices are similarly active, short-finned fish that occupy the same temperature and pH range: rummy-nose tetras, cardinal tetras, larger corydoras species and similarly sized fast-moving schooling fish. Avoid keeping them with small invertebrates — snails will be eaten (which is by design), and shrimp are at risk.
For a full, filterable list of compatible and incompatible species, see Amazon Puffer tank mates.
How do you tell male from female Amazon Puffers?
Sexual dimorphism in Colomesus asellus is minimal and reliable sexing is genuinely difficult — more so than in most aquarium fish. The one reported marker is that mature males may develop a longitudinal wrinkle or fold along the ventral midline (the belly), visible when the fish is relaxed rather than inflated. Females tend to have a smoother, rounder belly, particularly when carrying eggs.
In practice, these differences are subtle and inconsistent enough that most keepers cannot sex their fish with confidence. Buying a group of six or more from a mixed batch gives a reasonable chance of including both sexes.
Can Amazon Puffers be bred in captivity?
Amazon puffer breeding is rated very hard, and captive breeding records remain rare. Sexing the fish reliably, triggering spawning and raising fry are all significant hurdles. In the wild, spawning likely coincides with seasonal flood cycles — drops in temperature and water softness — that are difficult to replicate at home.
Hobbyists who have attempted breeding condition the group with live and varied foods, then simulate rainy-season conditions by gradually dropping temperature and softening the water over several weeks. Eggs are small and fry require infusoria and freshly hatched brine shrimp nauplii. This is an advanced project; for most keepers the priority is simply providing a healthy long-term environment for the group.
What diseases affect Amazon Puffers?
The most common health threats are ich (Ichthyophthirius multifiliis), presenting as white salt-grain spots, and velvet (Piscinoodinium), which causes a dusty gold sheen on the body and rapid breathing. Both are stress-triggered and water-quality-related. Wild-caught fish may also arrive carrying gill flukes or internal worms.
Prevention: quarantine all new arrivals for at least four weeks, maintain stable clean water and feed a varied diet. Puffers lack visible scales, which can affect medication tolerance — verify compatibility before treating.
Health note: medication dosing and disease diagnosis are beyond the scope of a care profile. For sick fish, confirm symptoms against a reputable veterinary or fish-health source before medicating, and adjust doses appropriately for scaleless fish.
How long do Amazon Puffers live?
With good care, Colomesus asellus lives 5–10 years in captivity — a substantial commitment for a community fish. Most specimens are wild-caught adults of unknown age, so robust care from day one is the best way to maximise the time you have with them.
The keys to longevity are consistent water quality, a varied diet that always includes hard-shelled food, a stable group of at least six conspecifics, and avoidance of stressors like aggressive tank-mates or overcrowding. A well-kept group will stay active, curious and characterful for the better part of a decade.
Frequently asked questions
Is the Amazon puffer safe in a community tank?
Unlike most puffers, C. asellus is genuinely peaceful toward other species and its own kind. It will not shred fins unprovoked, but keep it with similarly active, short-finned fish — avoid slow, long-finned species like bettas or fancy guppies that may be nipped opportunistically.
Why does my Amazon puffer need snails in its diet?
Puffers have ever-growing beak-like teeth (fused plates). Without hard-shelled food such as small snails, bladder snails or clam meat, the beak overgrows and the fish can no longer eat. Snails once or twice a week keep the beak naturally worn.
What you need to keep a amazon puffer
The baseline is a heated, filtered 120 L+ tank: a reliable heater to hold 23–28 °C (73–82 °F), a gentle filter that won't batter a amazon puffer in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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