Juvenile iguana on eating habits?

I have a 9 month old iguana and I can't keep her from eating EVERYTHING.... I have a 12' by 14' tropical enclosure and I have basilisks and water dragons which I periodically feed mice to... the only problem is that my iguana gorges on the mice!!!, and b4 I get greef for housing them together, the lizards all get along and they have more than enough room..... but regardless, how do I get the iguana to become a vegetarian again?