With the meeroos I am convinced that the only way to get new traits out is to mix those if wich its known they have exotics in their families. And jay! I am at work, cant coax the nest, but saw my 2 koi/nile OS gave me a koi Azure!
http://www.worldofmeeroos.com/meeroos/meeroo/1205987

It has Koi, Painted Nile and Emperor in the background.