Put it this way, if it was an oscar, I'd force it onto pellets...if it starved him for a bit, then so be it. I just think it's very important for providing a well-balanced diet of what they require. Fortunately I haven't ever needed to do this, but I've heard that it works quite well. Just takes some will-power not to give in to their 'feed me' dance, lol.
But in your case we are talking about a completely different fish...of which I know very little...
I'd hate for you to attempt this method, only to find that your fish ends up starving itself to death. I doubt it would come to that, but some fish can be very finicky when it comes to this and perish as a result. :?
What condition is he in now...healthy? Skinny?
That might dictate your course of action, at least to some extent.
I guess what I'm trying to say is that if you feel he's in good condition and strong enough to handle the 'starvation' (offering only pellets every so often until he starts eating them regularly) approach I outlined above, then I'd go for it. If you think there's a decent chance this might result in him kicking the bucket from starvation (which I doubt, but like I said I don't have experience with these guys), then don't.
Wow, that probably didn't help you much...sorry...
Maybe TFG and some of the others who are more experienced with the big guys can be of more help.