i have one about 6 inches who is moderately happy in a 55 - he pretty much sticks to one end of it. [ probably my fault . need to improve my aquascaping ]. my lfs suggested a 75g should be ok when he gets bigger, but will try to find a 125g used if possible.. he was over 4" in a 20 long tank and quite friendly. i raised him on ghost shrimp first. then for variety he got crickets, mealworms and night crawlers. he would eat these out of my hand untill i went on vacation. the lady who fed him said he wouldnt come to the surface for 5 days and on the 6th day he snatched the worm out of her hand. his mood has been odd ever since. like i betrayed him by leaving for a week. refuses to eat nightcrawlers or do the hand feeding thing. now only loves pond snails, which i luckily get for free from my lfs [ but they are running out! yikes ], and live juvenile crayfish [about 1.5"]. he is not an overly aggressive fish and only attacked the tail of a blood parrot recently. but in the fahakas defense, the parrot had been crowding his space since he'd never been bitten before. Fahakas like sand instead of gravel. and mine enjoyed having a stump to chill out under. and i swear he liked watching tv. but now hes in a tank where he cant see it.
been looking for other fahaka owners as mine is the only one i've known and it helps to hear other peoples experiences..