It is a tropical, marine and brackish water-dwelling catfish which occurs between Colombia and Brazil.

It inhabits a depth range between 1 and 50 m (3.3 and 164.0 ft).

[3] Cathorops spixii feeds on a variety of crustaceans, including amphipods, copepods, isopods; as well as bony fish and benthic invertebrates.

[4] It is preyed upon by Arius parkeri and Elops saurus.

[3] The species epithet refers to biologist Johann Baptist von Spix.