I expect the numbers of places these are kept is very low. I kept some years ago, but they are currently protected by WA and OR, and last I looked CA had a limit [as for most species]. They're not good candidates in captivity. They're cryophilic, normally living in water which is 8-12C, and at 17C they start to suffer. They can handle higher temperatures only for short times, and only if acclimated. In short, they MUST be chilled. They also need the water to be clean and well oxygenated. They normally live under rocks at the edges of waterfalls and in or beside he shallow parts of mountain creeks. Many of the adult-sized animals encountered still have tiny gills - which is all they ever have or need to get oxygen in that environment.
The combination of low heat tolerance, need for clean, flowing, oxygenated water, and legal protection makes them unlikely captive candidates. That said, I have a terrarium project set aside, in hope I'll get around to actually completing it and obtaining permits. It's hard enough working with tailed frogs, and torrents are more demanding.
