I've had the Goliath since February and at first I was just concentrating on getting him fat on cut catfish and tilapia. And after he got very comfortable in the tank I started starving him. It took about 50 ish days and he started accepting pellets today! And having my bambusa as a teacher fish definitely helped. Both of them are around 7" now. Here is a video of the gatf and the bambusa eating some hikari sticks and massivores: