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Skunk cory

Corydoras arcuatus

Recognizable by the elegant arched black band running from the mouth, through the eye, along the back to the tail — like a black arc drawn with a brush. Native to the Amazon basin (Brazil, Peru, Ecuador, Colombia), it is an active, social Corydoras that becomes significantly more expressive in large groups. Breeding considered more difficult than cousins C. aeneus or C. paleatus. Like all Corydoras, it is scaleless and salt-sensitive: avoid salt treatments.

Taxonomy
Class:Actinopteri
Order:Siluriformes
Family:Callichthyidae
Subfamily:Corydoradinae
Genus:Corydoras
Species:Corydoras arcuatus

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Water Temperature

22 - 28 °C

pH Value

6 - 7.5

Water type

Freshwater

Tank level

Bottom

Adult size

5 cm

Minimum tank volume

>= 60 L

Minimum group

>= 6

GH

2 - 15 dGH

KH

1 - 7 dKH

TDS

40 - 295 ppm

Conductivity

63 - 461 uS/cm

Species description

Geographical Origin and Habitat: Upper Amazon River basin in Peru and Ecuador. Found mainly in small tributaries, oxbow lakes and slow streams with sandy bottoms rich in vegetation and dry leaves.
Taxonomy and Morphology: Skunk Corydoras (Corydoras arcuatus). Characterized by the distinctive uninterrupted black band running along the entire back. Rounded snout and compact armored body.
Social Behavior: Schooling species, peaceful and quiet. Essential to keep them in groups of at least 6 specimens to replicate natural dynamics and prevent stress and shyness.
Coloration and Sexual Dimorphism: Whitish-gray body crossed by a thick and clear arched black stripe (hence "arcuatus") that goes from the mouth, passes over the eye and runs along the back to the base of the tail. Females are rounder.

Care, breeding and tankmates

Aquarium Setup: Tank of 60-80 cm (24-32 inches). Mandatory use of non-sharp fine sand for the well-being of the barbels. Roots, floating plants to shield the light and ceramic hiding places complete the layout.
Diet and Feeding: Bottom omnivore. Feeds by rummaging the sand. Administer specific feeds for bottom fish, bloodworms, daphnia and tubifex. Do not rely solely on the leftovers of other fish.
Water Quality: Prefers soft and slightly acidic waters, but is very adaptable if the water is well oxygenated and nitrate-free. Requires regular siphoning of the sand to avoid bacterial infections.
Compatibility and Cohabitation: Ideal companion for small Tetras, Rasboras, Otocinclus and peaceful dwarf Cichlids. Given its small size, it should not be paired with large predators that could swallow it whole (choking on the spines).
Aquarium Breeding: Similar to other Corydoras: stimulated by cold water changes. The eggs (very small) are laid on leaves or glass in areas of strong current. Parents may prey on their own eggs.
Risks and Diseases: Barbel infections caused by unsuitable gravel are the main cause of death in the aquarium. Avoid sudden osmotic changes during water changes.

Geographic Origin and Distribution

Upper Amazon River basin in Peru and Ecuador. Found mainly in small tributaries, oxbow lakes and slow streams with sandy bottoms rich in vegetation and dry leaves.

Origin

Amazon, Orinoco, and Guianas

Fish profile

Temperament
Peaceful
Corydoras arcuatus are peaceful, social schooling fish that thrive when kept in groups. Keeping them in numbers of at least six individuals greatly reduces their stress and promotes natural behaviors. They are completely harmless to plants and other tank inhabitants.
Diet
Omnivore
These are omnivorous bottom feeders that require a varied diet to thrive. Their meals should include high-quality sinking pellets, wafers, and live or frozen foods like bloodworms. A balanced diet ensures proper growth and vibrant coloration for Corydoras arcuatus.
Sex ratio
Specific M:F ratio
Maintaining a ratio of two or three males for every female is ideal for breeding purposes. This ratio encourages natural spawning behaviors and increases the chances of successful fertilization. In non-breeding community tanks, the exact ratio for Corydoras arcuatus is less critical.
Feeding frequency
Twice daily
They should be fed small amounts once or twice a day. It is important to provide only what Corydoras arcuatus can consume within a few minutes to prevent water fouling. Occasional fasting days can also be beneficial for their digestive health.
Bioload
Low
The Corydoras arcuatus has a relatively low bioload compared to many other species of similar size. They are efficient scavengers that help keep the substrate clean, which slightly offsets their waste production. However, adequate biological and mechanical filtration is still necessary to maintain optimal water quality in the aquarium.
Flow
Strong
They prefer moderate water movement that simulates their natural riverine habitats. A gentle current provides necessary oxygenation without exhausting the fish. Avoid overly strong flow that could sweep Corydoras arcuatus away or cause stress.
Jump risk
No
Reproduction
Oviparous
Breeding Corydoras arcuatus in captivity is possible but requires specific water conditions and conditioning. They are egg layers that typically deposit their adhesive eggs on broad leaves or the aquarium glass. Parents may eat the eggs, so it is often best to raise the fry in a separate tank.
Compatibility & tankmates
Community
They are incredibly peaceful and make excellent additions to community aquariums. Corydoras arcuatus gets along well with most other peaceful, similarly sized fish. Aggressive or large tank mates should be avoided as they may intimidate or harm them.
Tank level
Bottom
They are obligate bottom dwellers that spend the majority of their time on the substrate. Corydoras arcuatus constantly rummage through sand or smooth gravel in search of food. Very rarely will they be seen swimming in the middle or upper levels of the water column.

Window to the official scientific data of the species

Data synced on: 06/15/2026

Scientific Parameters & Models

Trophic level
2.9 ± 0.3 se
Resilience
Medium (1.4 - 4.4 years)
Phylogenetic uniqueness (PD50)
0.5
Bayesian Length-Weight
a = 0.00741, b = 3.14
VulnerabilityLow vulnerability (10 / 100)

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Variants and close relatives

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Last updated: 06/30/2026
Skunk cory (Corydoras arcuatus) Care Guide & Tank Setup | Atlarium