With a little love and care, you can easily rear the Austrolebias nigripinnis (Argentine Pearlfish), one of the strangest fish for your aquarium.

It is a species of killifish from the Rivulidae family. This species is widely found in the Lower Parama and Uruguay river basins in South America.

In this article, we will pass information regarding the care and management of Argentine Pearl Killifish while rearing in the aquarium.

Austrolebias nigripinnis Stats

Family Rivulidae
Scientific Name Austrolebias nigripinnis
Common Name Black Pearl Killifish
Size Up to 2.75 inches (7 cm)
Habitat South America: Lower Paraná and Uruguay River basins
Min. Tank Size 15 gallons
Diet Carnivorous, will eat flake, frozen and live foods
Behavior Aggressive to its own kind and others. Keep one male with several females
Water Temperature 64-75 °F (18-24 °C) pH range: 6.0 – 7.0; dH range: 5 – 12
Care Medium; needs good water conditions and frequent partial water changes
Population 1 male and 2-3 females for 10.5 gallons (40 liters)
Community No, keep in a specific tank
Hardness 1-8 NK°
Suitability For the specialist
Note This is an annual species

Species Summary

Argentine Pearl Killifish or Austrolebias nigripinnis are named “blue chromide” for their blue pearl-like spots in their bodies and fins.

Their overall color ranges from light blue-gray to dark gray, and the fin has dark colors with blue spots. Females are lighter than the male. Males usually possess a blue-black body color that extends into their fins.

This species is sensitive and requires frequent water changes in captivity. They need cooler water with an optimal temperature of around 68-71 °F. The water tank should contain a minimum of 15 gallons of water with a pH of about 6. High temperature (over 77 °F) decreases their survivability in the water.

– Habitat

This group of annual species of Killifish is native to South America. They are widely found in several regions of Argentina and Uruguay in the river basin area and Lower Parana.

This species inhabits the cooler waters and is more likely to be found in the tank’s bottom in captivity. In their native environment, the surface of their living water often freezes.

– Tank Mates

You can easily keep your Killifish with some other mates in the tank. These may include some smaller catfish varieties like Rainbowfish and other peaceful fish such as Tetras, Danios, etc.

Killifishes are usually school fish when in the wild, which means they need to be kept in groups for their optimum health and well-being.

They can quickly get stressed when left alone. But please remember, keeping two or more male Killies is dangerous. They can be aggressive towards each other and fight for themselves. It’s best to maintain the proper male and female ratio (1:10). Just make sure about maintaining cool water while rearing those species together.

– Austrolebias nigripinnis Care

Keeping a Blackfin Pearlfish is not so tough. You just need to change the water frequently, such as 50 percent for every five to seven days, and never overfeed them. You can easily keep a pair, trio, or even two pairs of this Austrolebias nigripinnis in a 3-gallon tank without any filtering system. You just need to provide some floating plants within the tank and some jar with coco peat where they can lay their eggs.

These fish do very well in cool water temperatures. When the temperature increases, they start suffering. The ideal temperature for their healthy living is 68-71 degrees Fahrenheit. Although temperature below 50 degrees causes no problem, above 77 degrees is tough for them to survive.

– Breeding

This species requires an optimal temperature for their breeding in captivity, which is 59 to 68 degrees Fahrenheit in their breeding tank. The cooler water is essential to stimulate their spawning that is critical for breeding.

Austrolebias nigripinnis are bottom spawners, meaning they lay and deposit their eggs in any substrate within their breeding tank. These substrates may include coco peat inside a jar.

The breeding habits of these fish in their native habitat are fascinating. During the time of breeding, both the male and female are ready for spawning. In this situation, the male swims back and forth and around the female to display their most attractive colors.

After showing off his excellent finnage, the male swims along by lowering his mouth and starts burrowing into the bottom of the substrate to find a suitable place for laying eggs.

In the captive condition, the breeding pair dives into the coco peat to deposit their eggs during spawning. You need to observe the time of spawning carefully.

After spawning, just remove the peat from their breeding tank and squeeze most of the water out of the peat. You need to keep the peat that contains the eggs in a dark and cool area since these are sensitive to light.

You can easily store the eggs for several months to years in this condition. Also, you can collect the eggs and incubate these into a plastic bag for two to four months. It requires half-inch deep water for the egg to incubate. Later, place those eggs in soft water to promote hatching.

– Gender Identification

Sexing is very easy in this species of pearlfish. Gender identification is usually done by gross observation of the coloration of the fishes. This fabulous species is well known for its blue chromide coloration. In general, both the male and female have a dark brownish stripe.

The male body is usually composed of a general dark blue and blue-green coloration on the fins. Pearly white spots are present on their body and fins. Females comprise an ochre or yellow-green color mix with brownish stripes comparable to the graining on marble. The margins of the male anal, dorsal, and caudal fins possess dark brown coloration.

– Diet

The Blackfin Pearlfish depends upon the insects and small crustaceans in the wild. This species prefers live foods like daphnia, mosquito larvae, glass worm, tubifex worm, and white worm.

But in the aquarium, you can provide a variety of food that they will accept. You can quickly source various diets such as live, frozen, or freeze-dried foods comprising brine shrimp, blood worm, or tubifex worms.

Regular feeding with a variety of diets is essential for the Austrolebias nigripinnis. This helps to maintain their optimum health and coloration. Nowadays, you can find various commercially available flakes and pellets for these aquarium fishes. The growth rate of the Pearl Fish fry is unbelievable.

These Pearl Fish fry have tremendous appetites and require feeding at least five times per day. A proper supply of live feed helps them to reach their adult size within eight weeks. They become ready to reproduce within three months of age. In some regions, they may need four months during the wet season to gain their maturity.

– Tank Setup

Argentine Pearl Killifish (Austrolebias nigripinnis) prefers soft and acidic water to live. Their tank should have plenty of hiding places for them, so build those hiding places by placing some live plants, rockwork, woodwork, or driftwood branches. They require these hiding places for their breeding.

Relatively, you can easily keep this Austrolebias nigripinnis in your home aquarium. They usually spend most of their time at the bottom of the tank to search for food within the substrate. You can provide a dark, sandy substrate or a base of small pea gravel in the tank. Please keep in mind that they require a minimum of 15 gallons of water in their tank.

– Diseases

Luckily, Austrolebias nigripinnis is relatively free from some major diseases. No OIE-reportable condition has been listed for this species. But a spontaneous infection of Glugea anomala is reported in this species. This fish parasite causes tumors in its host body and results in death.

The biology of microsporidian comprises some unique features. Among them, one of the most interesting features includes their ability to stimulate hypertrophic growth or tumor into their host body.

When a Glugea anomala invades the cell of Austrolebias nigripinnis, this builds a well-organized xeno-parasitic complex situation. Their symbiotic coexistence develops a hypertrophic condition into the fish’s body known as the Glugea ‘ tumors’.

– Austrolebias nigripinnis Lifespan

The life expectancy of Austrolebias nigripinnis is not so long. They hardly live eight months to a year in their natural habitat. Their time clock works in two ways. This starts after their breeding season that lasts for the next two months, and they only have two or four spawns. After then, they become senile and shriveled. This makes them quickly die within a few weeks.

Final Thoughts

In this article, we’ve covered a lot about the care and facts of Austrolebias nigripinnis.

Let’s sum up the information about Austrolebias nigripinnis to ensure you’re ready to have this species in your aquarium:

  • They require cooler water.
  • Their water tank needs to contain a minimum of 15 gallons of water.
  • They need frequent water change in their tank.
  • Their water should maintain a temperature between 64-75 °F with a pH range: 6.0 – 7.0 and dH range: 5 – 12.
  • Glugea anomala is the most common parasite reported in this species.
  • Their fry lives on foods like daphnia, mosquito larvae, glass worm, tubifex worm, and white worm.

The Argentine Pearl Killifish or Austrolebias nigripinnis is a colorful annual fish that can make your aquarium more fascinating. You can easily keep them with minimum care. They are considered the prettiest small freshwater fish in the world.

So why not give it a try to keep the world’s most adorable freshwater fish in your aquarium?

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