The habitat of the following species of Chilean freshwater siluriform fishes is studied: Diplomystes chilensis, Nematogenys inermis, Trichomycterus areolatus, T. chiltoni and Bullockia maldonadoi. N. inermis inhabits the potamonal region of rivers and streams (as the adults of D. chilensis); Trichomycterus and Bullockia inhabit the rhitronal region which is also occupied by young specimens of D. chilensis. These fishes occupy different habitats during their development in these regions. Largest differences exist between the adults: Diplomystes and Nematogenys prefer the deep zone of the Potamon of rivers and streams; trichomycterids prefer the dead water space in the benthonic part of Rhitron of rivers and streams. Diplomystes is a benthonic form of fast-running water; Nematogenys lives in slow-running water. The spatial distribution of these fishes in discontinuous both horizontally and vertically.