Corydoras Melanistius

Corydoras melanistius – Blackfin Cory Care Guide

Corydoras melanistius is a hardy and attractive species of Corydoras catfish native to the coastal rivers of northern South America, including Guyana, Suriname, and French Guiana. Known for its signature dark dorsal fin, iridescent body tones, and calm demeanor, the Blackfin Cory makes a great addition to peaceful freshwater aquariums. Its social behavior and active nature also make it an excellent species for beginners and experienced aquarists alike.

🐟 Species Overview

• Scientific Name: Corydoras melanistius

• Common Name: Blackfin Corydoras

• Origin: Guyana Shield region – coastal rivers of South America

• Adult Size: 2.5–3 inches (6–7.5 cm)

• Lifespan: 5–8 years (sometimes longer in well-maintained tanks)

• Temperament: Peaceful and social

• Swimming Zone: Bottom

• Behavior: Active, best kept in groups

🏡 Aquarium Setup

• Minimum Tank Size: 20 gallons (long tanks preferred for swimming space)

• Substrate: Soft sand or smooth gravel to protect barbels

• Décor:

  • Driftwood, broad-leafed plants, and smooth stones

  • Provide shaded resting areas and open substrate for foraging

• Lighting: Low to moderate

• Water Movement: Gentle to moderate flow

• Filtration: Sponge or low-flow HOB/canister filters

💡 Corydoras are sensitive to sharp substrate and uncycled tanks—provide aged, stable setups for best results.

💧 Water Parameters

• Temperature: 72–79°F (22–26°C)

• pH Range: 6.5–7.5

• Hardness: 3–12 dGH

• TDS: 100–250 ppm

• Water Changes: 25–40% weekly to maintain excellent water quality

🧪 Clean substrate is essential—poor bottom hygiene can lead to barbel erosion.

🍽️ Diet & Feeding

Corydoras melanistius are omnivorous scavengers. Though they may clean up uneaten food, they require regular feeding of balanced, sinking diets.

• Staple Foods:

  • Sinking pellets or tablets formulated for bottom feeders

• Protein Additions:

  • Frozen or live bloodworms, daphnia, blackworms

• Vegetables (occasional):

  • Blanched peas, zucchini, or spirulina-based pellets

• Feeding Frequency: 1–2 times daily; small portions are best

⚠️ Food must sink—these catfish are not surface feeders and may be underfed in busy tanks if not target fed.

🤝 Tankmates & Compatibility

• Great Tankmates:

  • Tetras, rasboras, peaceful barbs, dwarf cichlids, and other Corydoras

  • Community-safe livebearers, loaches, and non-aggressive gouramis

• Avoid:

  • Aggressive fish, fin-nippers, or large predatory species

  • Fast eaters that dominate food before it hits bottom

💡 Blackfin Corys do best in groups of at least 6, which encourages natural schooling behavior and reduces stress.

🐣 Breeding Tips

Breeding Corydoras melanistius in captivity is achievable with the right environmental conditions and cues.

• Spawning Type: Egg scatterers

• Spawning Setup: Separate breeding tank with soft substrate, fine-leaved plants, or glass

• Spawning Triggers:

  • Cool water changes (drop by 2–3°F)

  • Increased feeding with live or frozen protein foods

• Egg Care:

  • Remove adults after spawning to prevent egg predation

  • Use gentle airflow or anti-fungal treatment for egg development

• Fry Feeding:

  • Feed infusoria or liquid fry food initially, then baby brine shrimp as they grow

📝 Care Summary

🔧 Tips for Success

• Provide a fine sand substrate to allow natural sifting and foraging

• Keep in larger groups (6+) to reduce skittishness

• Maintain excellent substrate hygiene to prevent infection or barbel damage

• Consider floating plants to diffuse light and mimic their natural environment