well you could try melon, broccoli, zucchinni, potatoes, grapes, shelled peas, lettuce, frozen spinich, literally you could try any greens for this plec, you just gotta experiment. when they are older, or even now, you might want to drop a piece of prawn in and see if he grazes on that. just remember not to leave those things in too long, as some foul the water worse than others, so remove. i leave mine in for about half an hour, so maybe overnight, but its usually all gone anyway