Not sure, but I was told recently that they needed Brackish water when they reach adulthood. Due to the fact that they migrate towards the ocean when they hit maturity
They travel up river to spawn. So as of juvenile, they stay in freshwater and when they mature they move into brackish. But never known or heard anything about them being in full salt.
When they are young, they live in freshwater, and later in life travel down the stream into the Estuary, which is a mix between salt water and freshwater (brackish). As adults, they can be kept in full marine water.
Normally a Columbians Shark Catfish kept in freshwater won't last longer than a year or two.