Mini Cory
Gastrodermus 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.
Wassertemperatur
22 - 26 °C
pH-Wert
6 - 7.2
Wassertyp
Süßwasser
Tankfüllstand
Unten
Erwachsenengröße
4,5 cm
Mindesttankvolumen
>= 60 L
Mindestgruppe
>= 6
GH
2 - 12 dGH
KH
2 - 10 dKH
TDS
50 - 280 ppm
Leitfähigkeit
78 - 438 uS/cm
Artbeschreibung
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.
Pflege, Zucht und Mitbewohner
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.
Geografische Herkunft und Verbreitung
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.
Ursprung
Amazonas, Orinoco und Guayana
Fischprofil
- Temperament
- Semi-aggressive
- These catfish are incredibly docile, peaceful, and non-aggressive, making Gastrodermus 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.
- Diät
- Omnivore
- Gastrodermus 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.
- Lebenserwartung
- 3-5 years
- Erwachsenengröße
- 4.5 cm
- Geschlechterverhältnis
- School
- While sexing them can be challenging, a ratio of two or three males per female is generally recommended for breeding Gastrodermus 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.
- Fütterungsfrequenz
- Twice daily
- These active scavengers should be fed one to two times daily to ensure they receive adequate nutrition. It is important to offer Gastrodermus 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
- Low
- Gastrodermus 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.
- Fluss
- Stagnant
- In the wild, Gastrodermus 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.
- Sprungrisiko
- Yes
- The jump risk for Gastrodermus nanus is generally considered to be quite low. They are obligate bottom dwellers that spend the vast majority of their time sifting through the substrate. Occasionally, they will make quick darts to the surface to gulp atmospheric air, which is a completely normal behavior for this genus. Despite the low risk, it is still recommended to keep a well-fitting lid on the aquarium to prevent any accidental escapes during these upward dashes.
- Reproduktion
- Oviparous
- Breeding Gastrodermus 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.
- Kompatibilität & Tankkameraden
- Community
- This species is highly peaceful and makes an excellent addition to community aquariums. Gastrodermus 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.
- Tankfüllstand
- Bottom
- As classic bottom dwellers, Gastrodermus 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.
Wissenschaftliche Modelle & Parameter
FishBase
Zugang zu den offiziellen wissenschaftlichen Daten der Art
FishBase v25.04Daten synchronisiert am: 15.06.2026
- Trophäenniveau
- 3 ± 0,3 se
- Belastbarkeit
- Hoch (weniger als 15 Monate)
- Phylogenetische Einzigartigkeit (PD50)
- 0.5001
- Bayessche Längen-Gewichts-Beziehung
- a = 0.00741, b = 3.14
- AnfälligkeitGeringe Anfälligkeit (10 / 100)
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