The Austrolebias nigripinnis, commonly known as the Blackfin Pearl Killifish, is a rare and captivating annual killifish species native to the seasonal wetlands of Argentina and Uruguay. Growing to 3–4cm, this species is admired for its dark, velvety fins, subtle iridescence, and graceful movement in dimly lit, well-structured aquariums.

As an annual killifish, A. nigripinnis has a unique natural lifecycle adapted to temporary ponds. In the wild, it lives fast and breeds early, with eggs entering dormancy during dry seasons. This behavior can be replicated in the aquarium, making it a fascinating project for aquarists who want to experience the complete breeding and hatching cycle of a seasonal species.

🐠 Key Features:

• Scientific Name: Austrolebias nigripinnis

• Common Name: Blackfin Pearl Killifish

• Size: 3–4cm (adult)

• Lifespan: 6–12 months (annual species)

• Temperament: Peaceful, shy

• Difficulty Level: Moderate to Advanced

• Origin: Argentina, Uruguay (seasonal ponds and temporary wetlands)

• Ideal for species-only or breeding tanks

🌊 Water Conditions

This species thrives in soft, slightly acidic water with minimal flow and plenty of natural cover.

• Temperature: 18–22°C (64–72°F)

• pH: 6.0–7.0

• Hardness: 1–6 dGH

• Tank Size: 10 gallons or more

• Water Type: Freshwater

• Filtration: Sponge filter or very gentle flow

• Lighting: Low to moderate (prefers dim environments)

Use peat moss, coco fiber, or soft sand substrate to encourage natural spawning behavior and comfort.

🐟 Tank Mates

Due to their specific breeding habits and peaceful temperament, Austrolebias nigripinnis is best kept in species-only tanks.

Avoid:

• Aggressive or fast-moving species

• Fin-nippers

• Any tank mates that could disturb their eggs or outcompete them for food

This species is delicate and thrives best when kept in quiet tanks with minimal disturbance.

🍽️ Feeding Habits

As micropredators, they thrive on high-protein, small live or frozen foods.

Ideal diet:

• Baby brine shrimp

• Daphnia

• Microworms and grindal worms

• Frozen bloodworms or cyclops

• Optional: high-quality soft micro pellets

Feed 1–2 times daily, focusing on foods that support rapid growth and spawning readiness.

🧼 Care and Breeding Notes

As an annual species, A. nigripinnis has a natural cycle of rapid growth, early breeding, and dormancy through egg storage.

✅ To breed successfully:

• Provide peat moss substrate

• Allow natural spawning over 2–4 weeks

• Collect and store substrate slightly dried in a sealed bag for 2–3 months

• Re-wet substrate in a separate hatching tank

• Feed fry with infusoria and baby brine shrimp

Maintain stable, cool temperatures, as high heat can shorten their already brief lifespan.

🌿 Why Choose Austrolebias nigripinnis?

The Austrolebias nigripinnis is a hidden gem for aquarists seeking a deeper connection to nature's rhythms. With its beautiful contrast of dark fins and subtle color, its peaceful nature, and its unique breeding method, this species is perfect for dedicated hobbyists, breeders, and lovers of blackwater biotopes.

Experience the wonder of an annual life cycle—bring home Austrolebias nigripinnis today!