i have heard of two ways of artificially coloring fish (not counting the genetic method for glo-fish, the altered zebra danios). one method is injection, where color is added by needle injection to a certain area on the fish. examples of this method are painted glass fish, painted glass cats, etc. the other method is dipping. from what i read the fish are dipped in a chemical that strips off their defenses or opens up pores, or something. then dipped in the dye, and then possibly dipped into another chemical to help seal in most of the dye. i dont know how accurate this is, but in any case i dont like the dyed or painted fish. the colors fade, its horrible for them, and in the end you pay more for the same thing since the colors go away.