Lily wrote:

OK, that might explain why my terribly pretty bronze GF and its mostly
black and cream friend went a rich gold after a few weeks in my tank,
might it?? (They maintained their previous colouration out in the
pond, only changed when I brought them in)

Also some of the color enhancing food might cause this...

-D
--
"A positive attitude may not solve all your problems, but it will annoy
enough people to make it worth the effort." -Herm Albright