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The LD50 values and survival times of three pomacentrid species and two blennies were measured after being subjected to the venom of one of their predators, the olive sea snake, Aipysurus laevis. The species differed significantly in the speed of their responses to the venom. At high venom doses, blennies had higher survival times than pomacentrids, and in the latter group Dascyllus survived longer than did species of Chromis. In part, this may be related to differences between blennies and pomacentrids in degree of cutaneous respiration. Relative survival time was influenced by venom dosage; ranking order of species' survival times was different at low doses than at high ones, and taxonomic correlations broke down.

Venom from the olive sea snake, Aipysurus laevis, was injected into three species of prey fish, Chromis nitida, Dascyllus aruanus and Istiblennius meleagris. Their behaviour and ventilatory patterns were observed for 48 hr. Six progressive stages of envenomation, involving impairment of the locomotory and ventilatory systems, were identified. There were significant interspecific differences in time taken to reach various stages. In nature, the action of the venom not only would facilitate subduing the prey, but recovering it if it escaped.