The conditions the praecox is kept in can greatly affect their
appearance. In a bare tank where the fish is skittish and jumpy the
red color can greatly fade out. The blues don't seem to be affected as
much by conditions as the praecox has a reflective blue coloration.
Lighting will have a much greater affect on how the blue appears. To
really show the blue, you need to get the light shining from in front
of the fish and reflecting into your eyes. This will usually improve
the color of any fish but particularly the praecox. As most tank
lights are generally on top (and often pushed to the rear) the colors
are rarely shown to their best advantage. A fish photographer is going
to shoot the fish with the lighting reflecting off the fish and into
the camera, not really using the aquarium lights to catch the fish's
color.
On a note of the inbreeding problem, I'm seeing the praecox in USA
shops coming out of Asia. I've put these side by side with my own
stock, obtained out of Europe a couple of years ago and have noticed a
marked difference in the color. The blue is not as intense and red has
faded and decreased in area. I have also noticed a diet high in brine
shrimp can really help to improve the intensity of the red. I've had
females showing more red than many males I see in the shops.
Your best bet is to find somebody with some good stock and get some
offspring. But proper conditions and food may also do wonders for the
fish.
Cary Hostrawser
Minnesota Aquarium Society
http://www.mn-aquarium.org/
Rainbowfish Study Group of North America
http://home.earthlink.net/~sbuckel/index.html