Introduction to Family Aplocheilidae in Sri Lanka

Aplocheilus dayi | Male | Uditha Hettige©

Order: Cyprinodontiformes. Family: Aplocheilidae

Aplocheilus is a genus of killifish in the family Aplocheilidae. Their native range is in South and Southeast Asia. Several species, remarkably the striped panchax, A. lineatus, are important aquarium fishes. They are adapted to live just under the water surface. Hence, their dorsal fin is located much close to the caudal fin and their mouth is oriented upwards (Superior Mouth).

Sri Lanka is home to three species

Name Binomial Status
Ceylon killifish Aplocheilus dayi endemic, EN
Dwarf panchax Aplocheilus parvus non-endemic, LC
Werner’s killifish Aplocheilus werneri endemic, EN


  • Aplocheilus dayi (Steindachner,1892) / Sri Lankan Day’s Killifish / උඩ හඳයා / Uda Handaya

Aplocheilus dayi | Male | Uditha Hettige©

It is a very beautiful fish species endemic to Sri Lanka. This species belongs to the genus Aplocheilus with very colorful body patterns. Yellowish white spots on the head are important for identification. There are three black dots on the lateral triangle of the male’s body. In female females, there are about 6-7 vertical scales on the lateral part of the body above the anus. Males’ fins are pointed and females have fins with round edges. It can be seen in well-drained, slow-flowing streams and sometimes in lagoon-based ecosystems. Swimming is seen on the upper surface of the water plane. In particular, the Kelani and Kalu river basins reside in the wet zone. The maximum length is about 5 cm. A species endangered due to environmental degradation and habitat loss.

  • Aplocheilus werneri / Werner’s Killifish / ඉරි හඳයා / Iri Hadaya

Due to the white spot on the head and the stripes on the body, this small fish is known as the iri hadaya/ඉරි හඳයා in Sinhala. In memory of Mr. Werner, a German researcher who has done a number of experiments on animals, the Werners killifish, named Wernery, is aptly named Aplocheilus Werneri. The fish of the carp family is called the Killi Fish Killi Fish, derived from the Dutch “Kilde”. in the valleys of the Kalu Ganga, Bentara River, Gin Ganga, and Nilwala Ganga and canal areas of Nilwala Ganga can be seen above 200 m above sea level. Found in well-shaded, slow-flowing streams. Males’ fins are pointed and females have fins with round edges. Prefer swimming in the water’s upper echelon with clay or sandy bottom. Four or eight dark lines on either side of the fish add to their beauty. In the past, the population of the ornamental fish had been reduced by the density of Werner’s killifish. Endangered species due to human activities such as deforestation, insecticide use, and decomposition of river canals are also included in the Red Data Book by the World Conservation Union.

  • Aplocheilus parvus / Dwarf Panchax / කළපු හඳයා / Kalpu Handaya

Aplocheilus parvus | Male | Chamod Gunathilake©

Aplocheilus parvus, the dwarf panchax, is a species of killifish native to India and Sri Lanka. This species grows to a length of 6.3 cm (2.5 in). Males are colourful than females. And also males have pointed fins and females don’t.  Its natural habitats are sheltered fresh and brackish water tanks, small streams and rivulets overgrown with vegetation. Aplocheilus spp. are surface-dwelling predators preying on both aquatic and terrestrial insects.



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