I am not an expert, but it depends on what else is in your pond and how you are managing it. Lot of people pretty much manage catfish as put and take. They don't provide habitat for reproduction and have bass in the pond. The bass take out any offspring even if it comes about. In that scenario, you put in about 6" catfish, feed them, you count how many you take out, and after you take out about 50% you stock their replacements. Survival rate should be very good if you follow suggested stocking rates and take into account pond fertility and feeding.
If you do want your catfish to reproduce, you need to provide spawning habitat, like several old tires or other hollow places, and lot of cover for them to survive to decent size. Exactly at what point those sharp fins stop being palletable for LMB is unclear to me, but people here mentioned seeing dead bass impaled on a catfish in their mouth.
Catfish are also tolerant of low O2 content, so they are pretty hard to kill.
