Colostethus mertensi is a species of frog in the family Dendrobatidae, Endemic to Colombia.

[2][3][1] This terrestrial frog has been observed in cloud forests between 2100 and 2350 meters above sea level.

[1] The female frog lays eggs on the ground.

After the eggs hatch, the male frog carries the tadpoles to temporary ponds.

Its principal threats are habitat loss in the form of deforestation in favor of agriculture, both legitimate farms such as eucalyptus plantations and illegal crops, logging, and human habitation.