With regard to the Danubian Wels Budgie, you are probably right. I have only ever caught one Wels in my life and that came to a dead gudgeon on the Shoulder of Mutton Lake at Woburn in 1966.
However I have caught thousands of sharp tooth catfish in South Africa and a few Vundu in Zimbabwe. The range of baits I have caught these fish on? Here goes if I can remember them all.
Live and dead carp and several other species of fish, frogs both dead and alive, sausages, luncheoon meat, bread, worms, sweetcorn, maize meal paste, soap (that's right - soap), hard boiled eggs, locusts, crickets and scorpions, pieces of snake, various spinners and artificial lures as well as artificial flies. The best bait if I wanted to catch a African catfish to save my life would be a live frog or the head end of a small carp with all the guts hanging out.