Photo: NasserHalaweh (CC BY-SA 4.0) — via Wikimedia Commons
Agassiz's Corydoras (Corydoras agassizii)
A boldly spotted South American armoured catfish that earns its keep patrolling the bottom of any soft-water community tank.
Will it live with a Agassiz's Corydoras?
We compare each fish against your agassiz's corydoras on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Black Skirt Tetra✅ CompatibleSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blackline Rasbora✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Blackline Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Blood Red Tiger Pleco✅ CompatiblePeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Butterfly Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Desert Goby✅ CompatibleSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Diamond Tetra✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta✅ CompatibleSemi-aggressive · 6 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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Elegant Cory✅ CompatiblePeaceful · 6 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.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
- False Julii Corydoras✅ CompatiblePeaceful · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep False Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- German Blue Ram✅ CompatiblePeaceful · 6 cm · Hard care · 27–30 °C (81–86 °F)
- Compatible on the things that matter: shared water near 27–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Glass Bloodfin Tetra✅ CompatiblePeaceful · 6 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.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- GloFish Tetra✅ CompatibleSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Guppy✅ CompatiblePeaceful · 6 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.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 20–24 °C (68–75 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Neon Dwarf Rainbowfish✅ CompatiblePeaceful · 6 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Neon Dwarf Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Odessa Barb✅ CompatibleSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
- Panda Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
- Both are peaceful, and their water overlaps around 22–23 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Peaceful Betta✅ CompatibleSemi-aggressive · 6 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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Pearl Danio✅ CompatiblePeaceful · 6 cm · Easy care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
- Platy✅ CompatiblePeaceful · 6 cm · Easy care · 21–28 °C (70–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Samurai Gourami✅ CompatiblePeaceful · 6 cm · Hard 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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Slate Corydoras✅ CompatiblePeaceful · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Slate Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Smaragd Betta✅ CompatibleAggressive · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Three-striped Dwarf Cichlid✅ CompatibleSemi-aggressive · 6 cm · Medium care · 23–29 °C (73–84 °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.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Keep Agassiz's Corydoras 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)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Amano Shrimp⚠️ With cautionPeaceful · 5 cm · Easy care · 18–28 °C (64–82 °F)
- Agassiz's Corydoras may eat Amano Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Amazon Puffer⚠️ With cautionPeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Ash Lipped Apisto⚠️ With cautionSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras 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.
- Bright Diamond Tetra⚠️ With cautionPeaceful · 7 cm · Hard care · 24–28 °C (75–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras 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.
- Buenos Aires Tetra⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras 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.
- Colombian Tetra⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Colombian Tetra in a shoal of 6+ or it gets stressed and nippy.
- Congo Tetra⚠️ With cautionPeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras 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.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
- Melon Barb⚠️ With cautionPeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Melon Barb in a shoal of 8+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rounded Filament Barb⚠️ With cautionPeaceful · 7 cm · Medium care · 22–27 °C (72–81 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Rounded Filament Barb in a shoal of 6+ or it gets stressed and nippy.
- Tiger Barb⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Your 75 L tank is below the ~95 L this pairing really wants — crowding raises aggression.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Barb 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.
Agassiz's Corydoras care specs
- Care level
- Easy
- Breeding
- Medium
- Max size
- 6 cm (2.4 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 6–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 5–8 years
- Diet
- Omnivore
- Swim level
- Bottom
- Group size
- 6+ (shoaling)
- Family
- Callichthyidae
- Origin
- South America — upper Amazon basin, Peru and western Brazil
What is Agassiz’s Corydoras?
Agassiz’s Corydoras (Corydoras agassizii) is a small armoured catfish native to the upper Amazon basin of Peru and western Brazil. Adults reach around 6 cm (2.4 in), making it a compact, practical bottom-dweller for tanks of almost any reasonable community size. The body is cream to beige, densely freckled with bold black spots, and finished with a striking dark mask across the eye — a pattern so eye-catching it is regularly sold under names like “spotted cory” or even misidentified as Corydoras julii in the trade.
Unlike most fish, Corydoras lack scales and instead wear two rows of overlapping bony plates (scutes) from behind the head to the tail — giving them a subtly prehistoric profile. They also carry a short but sharp pectoral spine that locks erect when stressed; worth knowing when netting them. Agassiz’s Corydoras is completely peaceful, harmless to plants and invertebrates, and ranks among the easiest and most rewarding armoured catfish for a soft-water community aquarium.
Where does Agassiz’s Corydoras come from?
Wild populations come from the upper Amazon drainage of Peru and western Brazil. These rivers and streams are warm, soft and often tea-coloured — filtered through fallen leaves, root tangles and sandy substrate in the classic Amazonian blackwater style. The water is consistently low in dissolved minerals and free of sharp substrate. Replicating that warmth, softness and leaf-litter texture in the aquarium goes a long way toward keeping this species healthy and behaviourally active.
What size tank does Agassiz’s Corydoras need, and how should it be set up?
The minimum practical tank size is 60 litres (16 gallons) for a group of six — the smallest school size that lets the fish express natural behaviour. A longer footprint matters more than height; Agassiz’s Corydoras lives entirely at the bottom and benefits from horizontal swimming room. Fine sand is non-negotiable as the substrate — coarse or sharp gravel abrades the sensitive barbels quickly, opening the door to bacterial infections. Play sand or purpose-made aquarium sand works well.
Scatter dried Indian almond or beech leaves over part of the sand floor to replicate natural leaf litter and gently acidify the water. Driftwood and smooth river stones add cover. Low to moderate lighting keeps the fish active during the day; under bright, open conditions they tend to hide. Dense plantings of Java fern, Anubias or Amazon sword work well. Filtration should provide gentle circulation without blasting the bottom — a sponge filter or canister with a spray-bar diffuser is ideal.
What water parameters does Agassiz’s Corydoras need?
- Temperature: 22–28 °C (72–82 °F). Agassiz’s Corydoras tolerates the lower end of this range better than many tropical fish, but aim for 24–26 °C (75–79 °F) as a comfortable midpoint.
- pH: 6.0–7.5. Slightly acidic to neutral is ideal; sustained readings above 7.5 are not recommended for long-term keeping.
- Hardness: 2–12 dGH. Soft to moderately soft water mirrors their Amazonian origin. Very hard water (above 15 dGH) should be avoided.
Stability, as always, is more important than hitting exact target numbers. A cycled tank with consistent weekly water changes of around 25–30% is the foundation. Avoid sudden parameter swings when topping up with evaporation water or after large changes — Corydoras are hardier than their soft-water reputation suggests, but they are not immune to parameter shock.
What do Agassiz’s Corydoras eat?
Agassiz’s Corydoras is an omnivore that forages along the bottom, sifting through substrate for invertebrates, organic detritus and plant matter. Sinking foods are essential — pellets or flake that never reaches the substrate will leave the corydoras underfed while surface fish take everything.
High-quality sinking wafers or catfish pellets make a good staple. Supplement two or three times per week with frozen or live bloodworm, daphnia or tubifex to encourage active foraging and support good colouration. Feed at lights-out, when bottom-dwellers are most active, and remove uneaten food within a few hours.
What is the behaviour of Agassiz’s Corydoras, and which fish make good tank mates?
Agassiz’s Corydoras is entirely peaceful and poses no threat to any fish it can fit in the tank with. It is a social species that genuinely needs companionship — a lone cory tends to be shy and inactive, while a group of six or more roams the tank floor together in a way that is far more engaging to watch. The minimum recommended group size is six; eight to ten is better.
They inhabit the bottom zone exclusively, making them excellent partners for mid-water and surface-dwelling species that do not overlap their space. Good soft-water companions include small tetras (cardinal, ember, rummy-nose), pencilfish, apistogramma dwarf cichlids, small rasboras and other peaceful corydoras with matching water requirements. Avoid larger cichlids that will harass them and fin-nipping species such as tiger barbs.
For a full list of tested pairings, see Agassiz’s Corydoras tank mates.
How do you tell male from female Agassiz’s Corydoras?
Sexing Agassiz’s Corydoras is straightforward once the fish are mature. Females are noticeably broader and deeper-bodied when viewed from above — a well-conditioned female in a group is unmistakably wider across the belly than any male in the same tank. Males are consistently slimmer and slightly smaller overall. The difference is subtle in juveniles but obvious in adults of breeding age, particularly when females are carrying eggs. Viewing from above rather than from the side gives the clearest indication.
How do Agassiz’s Corydoras breed?
Breeding is achievable in the home aquarium and is rated medium difficulty. The most reliable trigger is a significant water change with cooler water — a 30% change 4–6 °C below tank temperature mimics the onset of Amazonian rainy season. Condition the group with live or frozen foods in the days beforehand.
Spawning follows the characteristic Corydoras T-position embrace: the male grips the female’s barbels while she releases eggs into her cupped pelvic fins, then presses them onto a clean surface — plant leaves, glass or smooth decor. Adults will eat the eggs, so moving the adhesive eggs or spawning plants to a rearing container improves survival. Eggs hatch in roughly 3–5 days at 24–26 °C (75–79 °F); fry become free-swimming within a few more days. Start with infusoria or commercial fry powder, then move quickly to baby brine shrimp and finely crushed sinking wafers.
What diseases commonly affect Agassiz’s Corydoras, and how are they prevented?
The most common problem is barbel erosion and infection — the sensitive whisker-like barbels are damaged by sharp substrate or rot when waste builds up on the tank floor. Use fine sand, maintain good filtration and vacuum the substrate during water changes to prevent it.
Bacterial infections (red blotch disease, general reddening) almost always trace back to poor water quality; keeping ammonia and nitrite at zero and nitrate below 20 ppm is the primary defence. White spot (ich) can appear after temperature drops or introduction of new fish without quarantine; stable conditions and a proper quarantine tank reduce the risk. Fungal infections follow physical injury or chronic stress.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. For fish showing signs of illness, compare symptoms against a reputable veterinary or fish-health resource before treating, and always follow product instructions carefully.
How long do Agassiz’s Corydoras live?
With good husbandry, Agassiz’s Corydoras lives 5–8 years — a solid lifespan for a small catfish and longer than many fishkeepers expect when they first bring a group home. The keys to reaching the upper end of that range are fine sand substrate, stable soft water, a well-maintained biofilter, a varied diet, and keeping them in a group large enough to prevent chronic stress. Fish kept in poor conditions or alone rarely live past three or four years; a well-managed group in a mature soft-water community tank routinely exceeds five.
Frequently asked questions
Is Corydoras agassizii the same as Corydoras julii?
No — they are separate species, though both are heavily spotted and frequently confused in the trade. True C. julii has small, distinct spots that do not merge into lines, while C. agassizii tends to have slightly larger spots and a more contrasting body pattern. Both are genuine Corydoras species kept in the hobby.
What substrate does Agassiz's Corydoras need?
Fine sand is strongly preferred. Corydoras forage by pushing their snouts into the substrate, and sharp gravel abrades the sensitive barbels around the mouth, leading to infections. Play sand or fine aquarium sand keeps the barbels healthy and lets the fish behave naturally.
What you need to keep a agassiz's corydoras
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a agassiz's corydoras in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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