In South Africa we target the Sharptooth Catfish.
Can grow to 45kg.
Attached is some pics of a few big ones.
In clear water we need to make long cast and use flies that push a lot of water.
In dirty water we splash for them using the other flies. They come to the surface to gulp air. Splash the flies close to where they come up and you can catch them
I caught one a few years ago that took me 45 minutes to land on a 8wt.
Had a 30lb Boga grip, started to lift the fish, the head came of the ground and the boga went of 30lb. Estimated the fish at over 22kg (55.88lb)