dc wrote in
:

Is this the only Lab. in your tank? Perhaps if you added some more
Labs. (preferably not of the same sex, though Labidochromis is hard to
tell apart) your Lab. will regain its dominate display colouration.

A few tips on sexing Labidochromis...

As adults the female Lab. will appear as a slightly diminished male. She
will be smaller, have a slightly less pronounced forehead, less striking
colouration, and more pronounced jowls.

The most commonly communicated trait is that the female tends to have far
less intense black markings on her ventral and anal fins, but due to the
length of time Labidochromis has been bred in captivity, this is not always
a good marker--often one can find females with striking black colouration
on her fins.

Most Labs. are sold as juveniles so sexing is many times harder than it is
for adults, which is already rather difficult to do. The best marker I
have found is the slightly more pronounced jowls and slightly less
pronounced forehead on the female which will become more evident as she
matures.

To take a good guess one must take all this into account and then closely
observe the fish for a time. More boisterous fish that often make runs at
others are most certainly males. Fish that appear slightly diminished may
either be females or non-dominate males. Fish that are diminished and do
not pursue other fish aggressively are more likely to be females; fish that
do this and are almost ignored by dominate aggressive fish are more likely
to be females; fish that exhibit all of these traits and behaviours and
possess some of the afore mentioned characteristics are very likely to be
females.