Maximum size : 5 cm

Blackfin Pearl Killifish - Austrolebias nigripinnis : Complete Fish Profile & Care Guide

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Caring for the Blackfin Pearlfish (Austrolebias nigripinnis) can pose challenges due to their skittish nature, yet their beauty is unparalleled when they are in optimal physical condition. These Killifish bring vibrant colours and lively activity to nano aquariums and planted setups. Given their shy disposition, it is crucial to select tankmates carefully to ensure they are not outcompeted for food. Ideally, companions of the same or similar size, such as Tetras, Rainbowfish, and Danios, would be well-suited for cohabitation with Blackfin Pearlfish.

Due to their schooling behaviour, it is important to maintain Blackfin Pearlfish in larger groups to promote their overall health and well-being. Solitary confinement can quickly induce stress in these fish. However, caution should be exercised when housing multiple male Killis together, as their territorial nature can lead to aggression. Therefore, maintaining an appropriate ratio of males to females is vital.

Creating a soft water aquarium with the presence of plants and bogwood is recommended for keeping these Killifish. Utilizing peat filtration and gentle water movement helps simulate the slow-moving waters that these fish inhabit in their natural habitat. As Blackfin Pearlfish are adept jumpers, incorporating floating plants provides essential surface cover and enhances their sense of security.

In terms of appearance, Blackfin Pearlfish typically exhibit a dark blue or blue-green colouration on their bodies and fins, adorned with pearly white spots. Males display additional dark brown pigmentation along the margins of their anal, dorsal, and caudal fins. Females, on the other hand, feature an ochre or yellow-green colouration with brownish stripes resembling the graining on marble.

Blackfin Pearl Killifish Photos

Sexual Dimorphism

Distinguishing between male and female Blackfin Pearlfish is a straightforward task. Males exhibit significantly more vibrant and darker body colouration compared to females. Additionally, their fins are adorned with distinct dark edging. In contrast, females display a notably duller colouration and lack the prominent edge on their fins observed in males.

Quick Facts

Scientific NameAustrolebias nigripinnis
Year Described1912
Other NamesBlackfin Pearlfish, Argentine Pearl Killifish, Dwarf Argentine Pearl
Max Size5 cm
Aquarium LevelBottom - Middle
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Diet & FeedingOmnivore
ReproductionEgg Depositor
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.0 - 7.0
GH 5 - 20
KH 1 - 8
Ideal Temperature
64 - 75
17 - 23

Natural Habitat

Blackfin Pearlfish are native to the Lower Paraná and Uruguay River Basins in Argentina, which are situated in South America. These fish inhabit naturally occurring cool and slow-moving aquatic habitats, including small rivers, streams, and temporary bodies of water with muddy substrates. It is worth noting that some of these water sources may experience periods of drying up during certain times of the year.


To successfully breed Blackfin Pearlfish, several key requirements must be met. You will need a tank with a water volume ranging from 10 to 25 litres, accompanied by a small jar or plastic container and a portion of well-boiled peat moss or coco-peat. Maintaining a water temperature between 64 and 75 degrees Fahrenheit is crucial. The tank should be equipped with a small filter, and regular water changes of approximately 90 per cent should be performed.

Introducing one male and two or more females to the breeding tank is recommended. Live food should be provided daily to sustain their nutritional needs. Whenever possible, breeding these fish in larger tanks with multiple pairs or trios is preferred, and the inclusion of hiding places further enhances breeding success. Each male should have a designated spawning container when breeding multiple males to prevent territorial conflicts.

During the breeding process, males exhibit captivating territorial behaviour to attract females to their designated spawning areas. They circle around the females, displaying vivid colours on their fins. When the female is receptive to spawning, she follows the male's lead. The male then presses his head against the layer of peat, and upon the female touching his belly, they both dive into the peat layer. It is important to ensure that the peat layer is sufficiently thick to facilitate successful spawning.

The spawning process occurs throughout the fertile lifespan of the fish, starting at approximately 5 to 6 weeks of age and continuing until they become elderly, weakened, or perish due to inadequate water conditions. The end-of-life stage can be expected within eight to eleven months, accelerated by higher temperatures. Incubation typically takes around six weeks at higher temperatures, while lower temperatures can extend the duration. Development periods of five to six months are also possible. Regular monitoring of the eggs is necessary to ensure the visible presence of the iris and the full development of the eyes.

Once the eggs reach the "eyed-up" stage, some peat should be removed and placed in cool water. If the fry hatch and begin swimming within a few hours, the remaining peat can be moistened. Immediately after hatching, feed the fry with brine shrimp or microworms. After a few days, transfer the fry to a well-filtered tank without peat moss to support their further development. It is essential to be cautious of strong water currents as juvenile Killifish may not be accustomed to vigorous turbulence, potentially leading to their demise.

Diet & feeding

The Blackfin Pearlfish readily accepts a variety of high-quality dried foods in the home aquarium, including granules, flakes, and sinking pellets. These modern food formulations have been meticulously developed to provide all the necessary nutrition to ensure the health and dietary requirements of your fish are met. While these staple foods deliver adequate nutrition, incorporating supplementary foodstuffs such as live, frozen, and freeze-dried options like bloodworm, daphnia, and tubifex once or twice a week can provide additional benefits for the overall health and well-being of your fish, although it is not mandatory for their diet.

It is important to note that while bloodworms can be offered as an occasional treat, they should not be relied upon as the primary staple diet due to their potential to be challenging for fish to digest and the risk of potential blockages. This fish exhibits omnivorous feeding behaviour in the wild, consuming some vegetable matter alongside other food sources. Most modern fish foods incorporate plant-based ingredients to accommodate this, but supplementing your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini can further enhance their nutritional intake.

Exercise caution to avoid overfeeding and promptly remove any leftover food the following day to maintain water quality and prevent potential health issues. By providing a balanced and varied diet, you can ensure the optimal well-being of your Blackfin Pearlfish in the home aquarium.

Other Killifish of interest