Multistore and multi language indexation

Opencart 1.5.6.4

Hello

I have a multistore, domain1.com is for spanish language and domain2.com is for portuguese language

The language configuration I used for for domain1 is: local>spanish for domain2.com is: local>portuguese

I read in forums Google only index default language

For the main site I can check Google is indexing only spanish, but for domain2 I found spanish and portuguese results and that´s bad for my seo because I´m duplicating content.

Are someone using multistore and multi language as I´m doing? I would like to know to index only one language for each domain

Thanks a lot