I got my jar about two weeks ago and I have tried all different types of food...
blood worms, super worms, food sticks, crickets and guppies.
and CRICKETS seem to be golden for my guy. He doesn't seem to ever get enough. Guppies seem to get his interest by my CK and Dat cash the guppies out before he can get close enough to them.
My jar is about 5" and in a 60g tank for now.