GloFish were never injected. Ever.
Unless you count injecting a plasmid of DNA coding for a jellyfish protein into the Nuclei of a zygotic Zebra danio.
There is nothing cruel about these fish, or keeping them in captivity. In fact, they pose absolutely no risk to the environment, as they are the antithesis of camouflage, and would be eaten within hours.
UNLIKE dyed fish, these can live a full and happy life of as good a quality as their natural brethren.
+1 for Stephen Colbert's GloCat.