Nijssen’s cory - Corydoras nijsseni

Scientific name: Corydoras nijsseni

Common name: Nijssen’s cory

Family: Callichthyidae

Usual size in fish tanks: 3 - 4 cm (1.18 - 1.57 inch)

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Recommended pH range for the species: 6.5 - 7.5

Recommended water hardness (dGH): 4 - 15°N (71.43 - 267.86ppm)

0°C 32°F30°C 86°F

Recommended temperature: 22 - 27 °C (71.6 - 80.6°F)

The way how these fish reproduce: Spawning

Where the species comes from: South America

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Bottom levels

Introduction

Corydoras nijsseni, commonly known as Nijssen’s Cory, is a small, peaceful bottom-dwelling fish native to the tributaries of the Rio Negro in South America. Their gentle temperament and unique appearance make them an excellent addition to community aquariums, particularly for aquarists seeking a smaller species of corydoras.

Food and Feeding

Nijssen’s Corys are not picky eaters but require a diet that reaches the tank's bottom to ensure they receive their share. Use fast-sinking pellets or flake food as the staple of their diet. To supplement, provide live or frozen treats such as bloodworms, brine shrimp, or white worms, which they will enthusiastically consume. Feeding during the evening hours may be beneficial as they are more active during this time.

Habitat and Tank Requirements

To replicate their natural environment, set up a tank with soft, fine sand or smooth gravel to protect their sensitive barbels. Provide plenty of hiding spots using rocks, driftwood, or dense planting, as they enjoy resting and exploring shaded areas. Suitable plants include Java Fern (Microsorum pteropus), Anubias (Anubias barteri), Amazon Sword (Echinodorus bleheri), and Cryptocoryne species (Cryptocoryne wendtii). These plants offer excellent coverage while tolerating the water conditions preferred by Nijssen’s Corys. Maintain water parameters within a pH range of 6.5-7.5 and hardness of 4-15°N (71.43-267.86 ppm). The ideal water temperature is between 22-27°C (71.6-80.6°F). Regular water changes are crucial to maintaining pristine water quality for this sensitive species.

Sexing

Sexing Nijssen’s Corys is relatively straightforward. Females are slightly larger and have a plumper body shape, especially when viewed from above, while males are slimmer and more streamlined.

Breeding

Breeding Corydoras nijsseni in an aquarium requires careful preparation. It is best to maintain a breeding group of one female with two males. Trigger spawning by performing regular water changes with slightly cooler water to mimic their natural rainy season. The female will scatter eggs throughout the tank, often attaching them to plants or surfaces. After 3-4 days, the eggs will hatch, and the fry will become free-swimming a couple of days later. Feed the fry newly hatched brine shrimp or micro worms to ensure proper growth and development.

Lifespan

With proper care, the expected lifespan of Corydoras nijsseni is 3-5 years, making them a rewarding species for dedicated aquarists.

Behavior and Compatibility

Nijssen’s Corys are peaceful and social fish that thrive in groups of at least five. They are ideal for community tanks with similarly non-aggressive species. Compatible tank mates include small, peaceful fish such as Neon Tetras (Paracheirodon innesi), Harlequin Rasboras (Trigonostigma heteromorpha), Ember Tetras (Hyphessobrycon amandae), and Guppies (Poecilia reticulata). Avoid housing them with larger or boisterous species like cichlids or large barbs, as these may stress or outcompete them. Their active and engaging behavior at the tank’s bottom makes them a joy to observe, especially when paired with compatible companions.

Short Description

Corydoras nijsseni, or Nijssen’s Cory, is a small, peaceful bottom-dweller perfect for planted community tanks. Their preference for group living and adaptability to various water conditions make them a popular choice among aquarists. Provide hiding places and maintain a clean, stable environment to keep them thriving.