All dye based colours will fade in time. This includes ALL of the colours used in normal printing processes. Colour photographs from wet chemistry photography (conventional photography) are just as susceptible, perhaps moreso.
Pigment inks tend to be more stable than soluble dye based inks so the Epson C series will be somewhat more stable than some others.
For maximum stablity have your pictures printed as Ilfochrome prints. This is silver based photography but the system used to form the colour is completely different to any other used processes. Other than that, store your pitures in the dark away from fumes. Note: "fumes" includes fumes given off by certain grades of paper - these can emit sulphur dioxide which will bleach the dyes
If you have to display them, place behind UV absorbing film or spray with a UV absorbing varnish. Both of these are available at art shops.
Hope that helps