I have read from a variety of sources that auratus can change gender if they are in an exclusively female tank. the dominant female changes from being gold with black stripes and picks up the dark blackish/brownish/blue coloring of the male auratus. however, i am not clear if this is an actual sex change or just a change in coloration to show dominance in the absence of a male. in other words, can an auratus female that "becomes male" fertilize eggs? i looked at the species article on this site and it does not mention anything about a gender or sex change.