Yellowfin Corydoras - Gastrodermus sp. C123, Corydoras sp. C123 Fish Profile & Care Guide
Introduction
The Yellowfin Corydoras (Gastrodermus sp. C123) is a rare and eye-catching species that makes a great addition to a peaceful community tank or shines in a dedicated species-only setup. What sets them apart is their bright yellow fins, especially in males, which you rarely see in Corydoras-type Catfish. Although they look like typical Corydoras, their scientific classification is slightly different. That's because the genus Gastrodermus was recently split from Corydoras and now includes the elegans group, along with the pygmy Corys. So, while they share many of the same traits, they've been given their own group based on updated research. These catfish may represent a regional variant of Corydoras elegans.
These are shoaling fish by nature, so they should always be kept in groups of at least six. Like most in this group, Yellowfin Corydoras are peaceful and do well with other small, gentle fish like Pencilfish, Tetras, Rasboras, and Danios. If you're trying to breed them or just want to enjoy their full behaviour, a species-only tank can be a great choice too.
One of the cool things about Yellowfin Corydoras is that they often shoal midwater, which is a bit unusual for Corys. Still, they'll spend time on the bottom, too, so make sure to give them a soft sand substrate to protect their sensitive barbels. Regular maintenance and clean water are key to keeping them happy and healthy. Add plenty of shaded spots using driftwood, rocks, and dense plants to help them feel secure.
In terms of looks, Yellowfin Corydoras have dark brown bodies with silvery-white markings. The head is mottled, and two faint stripes run along the back to the tail. The dorsal and tail fins are yellow with dark horizontal bands, and the other fins are solid yellow, making them really stand out in the tank.
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Sexual Dimorphism
Sexual dimorphism in Yellowfin Corydoras is relatively easy to observe, particularly in mature individuals. Females are generally larger and display a more robust, fuller body shape, a distinction that is most apparent when viewed from above. In contrast, males tend to be smaller and more slender, with fins that become more pointed as they reach maturity, whereas females typically exhibit rounder fin tips. These physical differences are subtle but reliable indicators when identifying the sexes, especially in well-conditioned adult specimens.
Quick Facts
| Scientific Name | Gastrodermus sp. C123, Corydoras sp. C123 |
|---|---|
| Other Names | Yellow Cat, Peru Yellow Cory |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Siluriformes |
| Family | Callichthyidae |
| Genus | Corydoras |
| Origins | Peru |
| Approx Max Size | 5 cm |
| Temperament | Peaceful |
| Aquarium Level | Bottom - Middle |
| Difficulty | Beginner - Intermediate |
| Shoaling | Yes |
| Best kept as | Groups 6+ |
| Diet & Feeding | Omnivore |
| Reproduction | Egg Depositor |
| Average Lifespan | Up to 5 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 6.0 - 7.5 |
| GH | 2 - 10 |
| KH | 1 - 5 |
| TDS | 80 - 200 |
| ℉ | 72 - 79 |
|---|---|
| ℃ | 22 - 26 |
Natural Habitat
The Yellowfin Corydoras is endemic to the Rio Nanay basin, located in the Amazonian region of Peru, South America. This species is typically found in shallow, slow-moving forest streams and tributaries, where it inhabits areas with sandy or fine gravel substrates. These environments are often shaded by dense overhead vegetation, resulting in diffused lighting and the accumulation of leaf litter and organic debris along the streambed. The water in these habitats is generally soft, slightly acidic, and rich in tannins, characteristics that arise from the decomposition of plant material and the minimal presence of dissolved minerals.
Breeding
Breeding the Yellowfin Corydoras in a home aquarium is achievable but often presents a degree of difficulty, requiring careful attention to environmental conditions. Spawning can typically be induced by introducing a substantial water change using slightly cooler, soft water, which mimics the natural onset of the rainy season in their native habitat and serves as a key spawning trigger. Once conditioned, females will lay small, adhesive eggs, often on the aquarium glass or broad plant leaves that have been pre-cleaned, while males follow closely to fertilise each egg. This behaviour may be repeated several times during a spawning session.
However, the eggs of this species are particularly susceptible to fungal infections, making it advisable for aquarists to consider adding a mild antifungal treatment, such as methylene blue, to the breeding tank to enhance egg survival rates. Under optimal conditions, incubation lasts approximately 3 to 4 days, after which the fry emerges and requires immediate access to nutrient-rich, finely powdered fry food. As they develop over the following days, the young fish can be transitioned to live foods such as newly hatched brine shrimp, which support healthy growth and development. Successful breeding of this species demands patience, attention to detail, and a stable, stress-free environment.
Diet & Feeding
The Yellowfin Corydoras primarily feeds on small invertebrates, insect larvae, and organic detritus found in the substrate. Using its sensitive barbels, the Yellowfin Corydoras sifts through sand and soft gravel to locate food particles, often working in small groups to stir up the substrate and uncover hidden prey. In captivity, this species adapts well to a varied diet, including sinking pellets, frozen or live foods such as bloodworms and daphnia, and vegetable-based wafers. Its scavenging habits make it a valuable addition to community aquariums, as it helps consume leftover food and maintain tank cleanliness. However, it should not be relied upon as the sole method of waste control.
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Published: 24 Mar 2025
Last Updated: 24 Mar 2025