The bare-hearted glass frog has the most transparent underside of all glass frogs, which allows for almost full visibility of their internal organs.
Bare-hearted glass frogs are similar in features to most glass frogs but have distinct characteristics. Like most glass frogs, they are small and green with yellow spots and transparent undersides. The transparent undersides are the main feature of most glass frogs, but the bare-hearted glass frog has the clearest underside, allowing almost full visibility of their internal organs.
Their transparent skin also makes them difficult to see, as well as their size. They are very small, with male frogs being 22–27 mm (0.87–1.06 in) long and females 24.5–29 mm (0.96–1.14 in) long. Other distinct characteristics of bare-hearted glass frogs are their forward-facing golden eyes and nostrils raised from their heads. They spend time moving throughout the forests and streams, their front fingers being less webbed and more isolated, while their back feet are heavily webbed, allow them mobility in trees and water.
Bare-hearted glass frog tadpoles are very small, less than 9.5 mm (0.37 in). They are brown with light undersides and have long bodies with pointed tails for swimming while they mature in the streams.