Five newly hatched froglets of the endangered Fijian ground frog Platymantis vitianus were transferred into a glass laboratory aquarium upon hatching, following egg-laying by adult frogs during the wet season in a purpose-built outdoor enclosure at the University of the South Pacific, Fiji. During captive management of the froglets, their body weight and food supply in the aquarium were closely monitored. All five froglets were successfully raised to 37 days old, at which time the aquarium was invaded by brown house ants Pheidole megacephala. This event was probably caused by excess ripe fruit, placed within the glass aquarium to attract small flies as food for the froglets, attracting the ants. The ants predated all five froglets. Future ex-situ designs for rearing P.vitianus froglets may consider incorporating measures such as aquatic protective barriers to prevent ants and other unwanted terrestrial invertebrates from entering captive-rearing aquaria and other enclosures.