Nothobranchius lucius

Nothobranchius lucius is a relatively large species of killifish and can be distinguished from the closely related N. melanospilus and N. makondorum, by its comparatively longer head, with a longer snout apparent in both males and females with the males having a thinner body. The snout is pointed with a subterminal mouth which faces slightly upwards. The dorsal profile is slightly concave on head and also concave from the nape to the posterior end of the dorsal fin; the caudal peduncle has a straight profile both dorsally and ventrally.^[1] Compared to many species in the genus Nothobranchius, N. lucius is rather dull in colour although an identifying mark is the presence of an orange line before the black margin of the caudal fin.^[2]

Nothobranchius lucius is found in a small area in southern central Tanzania, between Ifakara and the Kilombero river ferry. It appears to be replaced by the similar N. melanospilus to the east and by N. makondorum to the south of its range.^[2]

Nothobranchius lucius is found in seasonal pools and marshes where it reproduces in the wet season and the eggs enter diapause to hatch the following season.^[1] It is a predatory species and swallows smaller fishes whole.^[2]