That's a green texas, i.e. Herichthys carpintis (which is actually not a texas, i.e. Herichthys cyanoguttatum).
She is in her breeding gown. Was there any others alongside her in her LFS? If so she was probably ready to breed with him/her.
Alternatively, she could be affected by hormones from other cichlid species, seen it happen.
Alternatively, she could just be really excited.
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[EDIT]
Note that the texas and green texas are very different species, even if they're of the same genus.
The texas is in fact of a duller color, and have more evenly spaced smaller 'pearlings'. Their head is also more likely to be adorned with pearls/spots, rather than worms/lines. The green texas tends to be green, and do alternate into a blue color when it suits them. At least the var. Escondido does. Texas also grows to a more massive 30cm, whilst the green texas only grows to about 20cm.
Hope that helps.
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