LOL Shiari! Hamburguesa(baby Moor) wasnt sure if the grapes were food and it took him a while to catch on(he watched the adult eat it and decided to try it).
Lepperchan and shark_energy -- when I fed grapes I washed them in tap water, peeled the skin off and cut them into little pieces. For the orange just cut into sections. You can leave the peel on and they will just pick at the "meat." I cant rememeber which way it is but if you leave the peel on or off it will sink or float. I dont think it will change the pH if you have an established tank but you'll have to ask someone else for that one. As for bananas I have no idea!