The Magdalena Nectomys is a nocturnal rodent recorded along rivers in Colombia. Its hind feet are webbed, and it swims well.
Its back is dark brown, its flanks yellowish, and its belly gray. The hind feet have interdigital webs edged with silvery-white hairs.
It is described as nocturnal and solitary, swimming near water to feed on arthropods, small crustaceans, and other foods; nests are reported beneath logs or roots and in dense vegetation.
Along with arthropods, crabs and other invertebrates, it also eats fruit and fungi.
The hind foot has a narrow heel and a broad sole at the bases of the toes, covered with rounded scales.
An extinction-risk assessment has not been added yet.