The diet (a custom Silver Cup formulation with high pigment levels and
spirulina) we are using gives a good yellow/orange color to the fins and
sometimes the body of the males of our strains. The gold variations will
show red strips on a gold background. The older fish appear to show
better color and I have no idea why.
Using our diet without pigments, we don't see any color and even the gold
variations appear white. Some years ago, we did a study which tested the
same diet with and without the pigments and for zebra fish we obtained
better results with pigments and guppies did better without the pigments
-- the effects weren't very large, but good enough to make a business
decision (you don't need 95% confidence levels to make a rational decision
on what feed to use).
I have seen bacterial infections on some fish which will give a red color
to the fins -- but that is not good. This is more common around the base
of the fin and can be a very blood red color.
Dallas E. Weaver, Ph.D.
5542 Engineer Dr.
Huntington Beach, Ca 92649 [Only registered users see links. ] [Only registered users see links. ]