Mini Cory
Corydoras nanus
As the name suggests, it is one of the smallest and most slender Corydoras ever. The silvery livery is furrowed by fine blackish stripes running parallel on the flanks.
Water Temperature
22 - 26 °C
pH Value
6 - 7.2
Water type
Freshwater
Tank level
Bottom
Adult size
4.5 cm
Minimum tank volume
>= 60 L
Minimum group
>= 6
GH
2 - 12 dGH
KH
2 - 10 dKH
TDS
50 - 280 ppm
Conductivity
78 - 438 uS/cm
Species description
Geographical Origin and Habitat: Endemic to Brazil and Suriname (Maroni and Corantijn river basins). Inhabits placid shady forest inlets, swamps, or small streams with mostly dark and amber waters, characterized by dense deposits of soft organic debris.
Taxonomy and Morphology: The name "nanus" describes its minute size: it belongs to the Callichthyidae family and hardly exceeds 4.5 centimeters (1.8 inches), placing it among the dwarf sizes of the corys. Stocky, rounded profile and standard lateral armor of the genus.
Social Behavior: Mild and perpetually busy on the bottom. Extremely gregarious, exhibits deep stress pathologies if left alone. It is mandatory to insert large swarms (from 8 to 15 specimens) to observe it moving in unison on the sand with total confidence.
Coloration and Sexual Dimorphism: Very elegant and striped design ("striped pattern"): brilliant silvery background on which 3-4 dense and continuous horizontal blackish stripes stand out. Females, as per the manual for the genus, appear visually clumsiest, wider, and stockier compared to the slender males.
Care, breeding and tankmates
Aquarium Setup: Abrasive substrates prohibited. Requires a base of fine sand, preferably dark to enhance the silver of the livery. Structure shady refuges with half coconut shells or tangles of branched roots, combining dim light on the surface.
Diet and Feeding: Debris micro-predator: the tiny mouth requires fine baits. Floating foods are not recommended. Excellent to provide sinking microgranules for Corydoras mixed with copious bi-weekly doses of frozen Daphnia, brine shrimp, white worms, and grindal worms.
Water Quality: Maintenance in the classic tropical ranges (22-26°C / 72-79°F). Soft hardnesses (GH 2-12) and weakly acidic-neutral water (pH 6.0-7.2). The degradation of the bottom and the accumulation of ammonia are ruthlessly fatal, demanding excellent filtration but mild flow.
Compatibility and Cohabitation: Due to its stature, it is essential to pair it with peaceful mini-fish: Boraras, Hyphessobrycon, Nannostomus, and small Loricariids (Otocinclus). Never cross its path with rowdy fish, large Cichlids, Loaches, or nocturnal predators capable of swallowing it.
Aquarium Breeding: Reproducible by stimulating the school with cold "monsoon changes" (temperature drops of 3-4 degrees). After frantic T-chases, the large adhesive eggs are fixed to the glass or on fine vegetation. Promptly remove eggs or parents to avoid their immediate ingestion.
Risks and Diseases: The erosion of the delicate barbels on inadequate bottoms causes lethal and inoperable fungal/bacterial necrosis of the mouth. Extreme hypersensitivity to medications containing copper sulfate or to high levels of prophylactic salinity.
Geographic Origin and Distribution
Endemic to Brazil and Suriname (Maroni and Corantijn river basins). Inhabits placid shady forest inlets, swamps, or small streams with mostly dark and amber waters, characterized by dense deposits of soft organic debris.
Origin
Amazon, Orinoco, and Guianas
Fish profile
- Temperament
- Semi-aggressive
- These catfish are incredibly docile, peaceful, and non-aggressive, making Corydoras nanus perfect community tank residents. They are somewhat shy by nature and heavily rely on the presence of a school to feel secure and display their natural behaviors. Providing plenty of hiding spots such as caves, driftwood, and dense vegetation will make them feel more comfortable. They never bother other fish and often completely ignore species occupying the middle and upper levels of the tank.
- Diet
- Omnivore
- Corydoras nanus is an omnivorous bottom feeder that constantly scavenges for food in the substrate. Their diet should be primarily composed of high-quality sinking pellets or wafers specifically formulated for bottom dwellers. To ensure optimal health and coloration, supplement their dry food with live or frozen foods such as bloodworms, daphnia, and brine shrimp. They will also eat uneaten food that falls from the surface, though they should not be treated merely as a clean-up crew.
- Life expectancy
- 3-5 years
- This small catfish has an average life expectancy of 3 to 5 years in well-managed aquariums. Providing a stress-free environment with stable water parameters and a non-abrasive substrate is essential for their health. A rich and varied diet prevents nutritional deficiencies and supports their natural vitality.
- Adult size
- 4.5 cm
- The catalog's scalar value is 4.5 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 4.5 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Corydoras nanus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- School
- While sexing them can be challenging, a ratio of two or three males per female is generally recommended for breeding Corydoras nanus. Females are noticeably rounder and broader, especially when viewed from above, and tend to grow slightly larger. Males appear more slender and streamlined in comparison. Keeping them in a mixed-sex school naturally accommodates these ratios without requiring precise selection by the aquarist.
- Feeding frequency
- Twice daily
- These active scavengers should be fed one to two times daily to ensure they receive adequate nutrition. It is important to offer Corydoras nanus only as much food as they can consume within a few minutes to prevent water quality issues. Since they are somewhat nocturnal by nature, feeding them once right before the aquarium lights turn off can be very beneficial. Monitoring their feeding is essential, especially in community tanks where faster mid-water fish might outcompete them for food.
- Bioload
- Corydoras nanus has a relatively small bioload compared to larger aquarium fish. Due to their compact size, they produce a manageable amount of waste that standard filtration can easily process. However, because they must be kept in groups of at least six, the cumulative bioload should be considered when stocking. Regular water changes and good mechanical filtration are still necessary to keep the substrate clean where they dwell.
- Flow
- Stagnant
- In the wild, Corydoras nanus typically inhabits slow to moderately flowing streams and tributaries. They appreciate some gentle water movement in the aquarium, which helps keep the water well-oxygenated. However, excessive current or strong powerheads should be avoided as it can exhaust them over time. A standard sponge filter or a hang-on-back filter with baffled flow usually provides the ideal water dynamics for this species.
- Reproduction
- Oviparous
- Breeding Corydoras nanus in captivity is achievable but requires specific conditions to trigger spawning. A common trigger involves performing a large, slightly cooler water change to simulate the onset of the rainy season in their natural habitat. Females will lay adhesive eggs on broad-leaved plants, aquarium glass, or other flat surfaces. Once spawning is complete, the adult fish should be removed or the eggs transferred, as they may exhibit egg-eating behavior.
- Compatibility & tankmates
- This species is highly peaceful and makes an excellent addition to community aquariums. Corydoras nanus gets along perfectly with small tetras, rasboras, dwarf cichlids, and peaceful livebearers. It is crucial to avoid housing them with large, aggressive, or predatory fish that could bully them or attempt to eat them. As a schooling fish, they find safety and comfort in numbers of their own kind or similar Corydoras species.
- Tank level
- Bottom
- As classic bottom dwellers, Corydoras nanus occupies the lowest levels of the aquarium. They spend their days tirelessly exploring the substrate in search of morsels of food using their sensitive barbels. It is absolutely essential to provide a soft, sandy substrate to prevent damage to their delicate sensory barbels. Although they mostly remain at the bottom, they will occasionally dart to the water surface to swallow a bubble of air for intestinal respiration.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3 ± 0.3 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5001
- 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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