large catfish in 55

I would like to keep a couple large catfish in a 55, but need some ideas. Before you go off saying, "Oh you need a 1000 gallons tank for one of those and a slippery waffle 5000 filter with a 2000 dollar pump," let me say that once they reach a length of 18 inches or more, I am giving them to my friend who has a very large tank so dont start. I want one that eats feeder fish and looks cool, they have to be pretty big, like able to be 12 inches or more.
 
lol...I'm not going to touch this one.
 
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