Hey Jib, what Dloks and others has said had been our communal knowledge and experience for a while now. Mine included.I have seen people grow them to monster sizes.
Why do you say they are difficult to keep alive
We'd be more than happy to learn of new data and correct our view. Please tell us more if you will.
Bottom line, we know of a hundred or more of 2'-3' tigs firsthand from MFKers, and perhaps only of 1 or 2 douradas grown to 1'-1.5'.
That says a lot.
I am not counting Enrico Richter's superb two doradas or douradas of other keepers of Enrico's caliber, of which there appear many in SE Asia, Japan, as we don't know how they grew theirs, how long they had them, etc., neither can we ask them questions.
My own dourada experience is horrible and the reason behind it may or may not have anything to do with why we as a community fail to grow and keep dourada catfish. https://www.monsterfishkeepers.com/...toma-rousseauxii-aka-dorado-catfish-4.678571/