I wouldnt too if I was the lizard Seriously letuce is junk food for reptiles, very litle nutricional value and quite a few bads If your dragon wants to eat veggys give him mustard greens, water cress, Hibiscus and other dark leafys(no spinach). As for eating Ficus you can give him fresh figs wich come from Ficus carica and are very high in calcium, one of the best fruits. However try to avoid that your lizard eats ficus leafs by giving him other healtier leafs. It wont kill him if he eats them but try to avoid it, some animals react badly to the white latex that all Ficus have and can even have a alergic reaction. But I think your water dragon is safe Also make shure the plant your using hasnt been exposed to any pesticides, fugicides,etc. Plants brougthed from a shop should stay outside for many mouths, exposed to rain so to get clean of any toxins they migth have