Darker mask on C. sodalis

[jen.nelson]

Hello all,

I've noticed recently that a few of my Corydoras sodalis have developed a darkening of the area on top of their heads from their mouth to about their gills. No one seems unhappy, so I'm really more intrigued than anything. Is this a normal maturation color change, some sort of breeding signal, or are they just trying out a new look?

Thanks for your thoughts,
Jen