The reproductive and developmental styles of Aplocheilichthys johnstoni closely resemble those of other oviparous cyprinodont fishes reported in the literature. Reproductively it sorts to the guild of nonguarding phytophyllic broodhiders, is a daily, fractional spawner of relatively large, adhesive eggs. The length of the embryonic period varies between 14 and 19 days and the larval period can last for up to 30 days. Sexual maturity can be attained at an age of 150 days from fertilization. The embryology is described in detail and close comparison is made with the embryology of other cyprinodonts to highlight possible phylogenetic differences. Major differences with other cyprinodonts are in the rate of development, and heterochronic shifts in the appearance of certain structures in relation to each other. A discussion is included on the nature of development. It is suggested that development proceeds in a gradual stepwise fashion, interspersed with four major saltations, namely, fertilisation, onset of exogenous feeding, sexual maturity and death