My common will usually eat most fruit I put in the water right away. I just put in pieces he can swallow whole. Some times I'll give him a small piece of something he likes alot like fish first then put in the fruit if he won't eat it right away. I can't get mine to eat any greens though. What greens do you give yours and how do you give them to him? I've tried leave leaves of romaine in there and pieces of collard greens but i can't get him to touch it. I also put live plants in his tank for a month and he never touched them.