[3] With an adult snout–vent length of 15 to 17 mm (0.6 to 0.7 in), Excidobates captivus is a very small species of poison frog.

It was rediscovered in the same locality some seventy-seven years later and a single specimen has also been observed on the north side of the Marañón River.

In the breeding season, the male advertises his presence by calling from hidden positions among low foliage, emitting short "shrieks" at irregular intervals.

The tadpoles are transported on the parent's back to phytotelmata, temporary pools of water, and may be deposited in the axils of Heliconia plants.

The species is common in certain parts of its range and it is thought that its total extent of occurrence may extend to an area of about 7,350 square kilometres (2,840 sq mi).