Very slow growth, 2-3 inches a year, depends on a lot of things. do you have another tank as it will be a while before it could go in your 400 depending on the fish in there, to get off live foods you could try worms and crickets then move on to pellets. If it only eats fish, cut a prawn into long thin strips and loosely tie to a price of thread so when something pulls on it, it will come lose. Put that in the tank and jerk the thread so it looks like a fish. That should get him to eat that. After a while put pieces of prawn in the outflow of the filter and then just drop them into the tank. Start to introduce pellets with the prawns and work your way up
