Lavanis

Lavanis is a genus of small freshwater fish in the family Cyprinidae, native to the Lavanis River Basin in Southeast Asia. The genus currently includes two described species: Lavanis rivulus and Lavanis alba. The name Lavanis is derived from the Lavanis River, where the type specimens were collected.

Description: Lavanis species are slender, silvery fish reaching 5–8 cm in standard length. They have a single midlateral stripe and relatively large, rounded fins. Dorsal fin placement and scale counts help distinguish species.

Distribution and habitat: They are restricted to clear, slow-moving streams and floodplain wetlands within the river basin. Water temperatures typically range from 22–26°C with pH near neutrality.

Biology and ecology: Lavanis are omnivorous, feeding on small invertebrates and plant matter. They form seasonal schools and spawn during the monsoon when water levels rise. Spawning involves adhesive eggs laid among submerged vegetation.

Taxonomy and naming: First described by Rao and colleagues in 1992, the genus has undergone minor revisions as more specimens were studied. The two described species differ mainly in body depth, stripe width, and fin measurements.

Conservation: The Lavanis population is locally affected by habitat modification, pollution, and water extraction. No comprehensive IUCN assessment exists; several populations are considered vulnerable to ongoing degradation.

In culture and human use: Locally captured for subsistence and occasionally kept in home aquaria, though they are not a major trade species.