The Ceylon killifish (UDA HANDAYA / උඩ හඳයා)(Aplocheilus dayi) is a species of killifish endemic to Sri Lanka. This species grows to a length of . Males and females have a black dot at the rear end of the base of the dorsal fin. The females lay 50–150 eggs. The specific name of this fish honours the Inspector-General of Fisheries in India Francis Day (1829-1889), who first reported this fish, although he identified it as Aplocheilus panchax.

References

Tropical fish
Taxa named by Franz Steindachner 
Fish described in 1892
Ceylon killifish
Freshwater fish of Sri Lanka