The Lost River sucker (Deltistes luxatus), known as the c'waam (pronounced /tʃwɑːm/ CHWAHM) by the Klamath Tribes,[5][6] is a species of ray-finned fish in the family Catostomidae.

[10] The sucker eats a variety of animal material, including zooplankton, various other invertebrates, and periphyton.

[11] This fish is endemic to the Upper Klamath Basin straddling the border between southern Oregon and northern California.

Its range declined as dams were built, flows were diverted, marshes were dredged and drained, and exotic species were introduced to the area.

The landscape changed as it was altered for agriculture, livestock were transported in, trees were taken for timber, and riparian vegetation was cleared.

[7] About 70% of the wetlands surrounding Upper Klamath Lake have been impounded and drained, eliminating much of the habitat used by juvenile suckers during their development.

Healthy wetlands also absorb contaminants such as phosphorus, which in excessive amounts causes blooms of organisms, especially the cyanobacterium Aphanizomenon flos-aquae.

[7] A number of these species readily feed upon juvenile suckers, especially the fathead minnow and yellow perch.

[11] Conservation efforts include habitat restoration projects, hundreds of which have been started in the Upper Klamath Basin.