Dyscophus antongilii has no potent toxin comparable to a dart frog's. Its defence is mechanical and irritant. Threatened, it puffs up to look larger and harder to swallow, and if grabbed it releases a viscous white secretion from glands in the skin. The secretion is adhesive enough to gum up a small predator's mouth and can cause an allergic reaction and stinging in human skin and eyes.
The colour is a warning signal rather than a bluff about lethality, and the intensity varies. Females are the redder sex, while males tend towards a duller orange-brown. Juveniles are drabber and brighten with age.
The species has a narrow natural range around Antongil Bay in north-eastern Madagascar, and was for many years listed as Near Threatened before reassessment. It is often confused in the pet trade with Dyscophus guineti, the false tomato frog, which is more widespread; most captive animals sold as tomato frogs are in fact the latter species.