''Austrolebias nigripinnis'', also known as blackfin pearlfish, is an

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...

killifish A killifish is any of various oviparous (egg-laying) cyprinodontiform fish, including families Aplocheilidae, Pantanodontidae, Cyprinodontidae, Fundulidae, Nothobranchiidae, Profundulidae, Aphaniidae and Valenciidae. All together, there ar ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rivulidae The Rivulidae are a family (biology), family of killifishes in the order (biology), order Cyprinodontiformes. They are commonly known as rivulids, South American killifish or New World killifish. The latter names are slightly misleading, however, ...

. These annual killifish lives in temporary water bodies during the season, thus it undergoes its entire life cycle within the periodically drying-up temporary ponds in the

Río de la Plata The Río de la Plata (; ), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda, Colonia, Punta Gorda. It empties into the Atlantic Ocean and ...

Patos Patos is a municipality of the state of Paraíba in the Northeast Region of Brazil. It is classified by the Brazilian Institute of Geography and Statistics as a sub-regional center A. It is located in the Espinharas River valley, surrounded b ...

– Mirim and Mamoré basins in South Americal 0 Most species are small, less than in

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

, but a few reach , making them some of the largest killifish (only a few ''

Fundulus ''Fundulus'' is a genus of ray-finned fishes in the Taxonomic rank, superfamily Funduloidea, family (biology), family Fundulidae (of which it is the type genus). It belongs to the order (biology), order of toothcarps (Cyprinodontiformes), and th ...

'', '' Moema'' and ''

Orestias Orestias (), later refounded by Hadrian as Adrianople (Greek: Άδριανούπολις), was an ancient Greek settlement next to the Evros river in Thrace, near or at the site of present-day Edirne, and close to the current border between Turk ...

'' reach a similar or larger size).

Species

There are currently 46 recognized species in this genus:

References

10. {{Taxonbar, from=Q653758 Rivulidae Freshwater fish genera