EN

Killifish

Austrolebias viarius

Unknown

Overview

Austrolebias viarius is a small, colorful annual killifish endemic to temporary wetlands in Uruguay and southern Brazil. Males display vibrant blue and yellow coloration during breeding season, while females are more subdued in appearance. These fish play a crucial role in temporary pond ecosystems as both predators of invertebrates and prey for birds and larger fish.

Austrolebias viarius faces severe threats from habitat destruction due to agricultural expansion, urban development, and wetland drainage in its limited range. The species' dependence on temporary pools makes it particularly vulnerable to hydrological changes and pollution from agricultural runoff.

Threat summary

Habitat

This killifish inhabits shallow, temporary pools and seasonal wetlands that fill during rainy periods and dry completely during drought seasons. These ephemeral water bodies are typically found in grassland depressions with muddy substrates that preserve the species' drought-resistant eggs.

FRESHWATER· major

Other threatened species in Rivulidae

VU

Peixe-anual

Austrolebias varzeae

Unknown
VU

Rachovia hummelincki

Unknown
VU

Austrofundulus guajira

Unknown
CR

Austrolebias bagual

Unknown

Threatened in Uruguay

Calidris ferrugineaVU

Calidris ferruginea

Declining
Acipenser gueldenstaedtiiCR

Acipenser gueldenstaedtii

Declining
EN

Melanophryniscus pachyrhynus

Unknown
Chilean FlamingoVU

Chilean Flamingo

Phoenicopterus chilensis

Unknown

Frequently asked questions

Why is Killifish classified as Endangered?
Killifish is classified as Endangered — facing a very high risk of extinction in the wild — because population numbers are declining steeply and key habitats are under sustained pressure. Austrolebias viarius faces severe threats from habitat destruction due to agricultural expansion, urban development, and wetland drainage in its limited range. The species' dependence on temporary pools makes it particularly vulnerable to hydrological changes and pollution from agricultural runoff.
Where does Killifish live?
Killifish occurs in Uruguay. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Killifish?
The main threats to Killifish are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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