emperor diet question

[fishfeen]

i bought a juvi emperor like a 1.5 years ago and haven't fed him sponge based food (angel formual) until recently. he is currently changing into an adult and i think he's almost done. is it too late for him to develop all the colors he's suppose to have since he didn't get sponge until now? it seems like he's missing parts of the blue border around his mask. the blue border is there but doesn't look complete. any help is much appreciated, thanks.

 

[fishfeen]

the emp is about 5" now. i've been feeding it mysis shrimp, seaweed select, frozen brine, frozen blood worms, dried krill, dried shrimp, spirulina flakes, formula 1 and 2 flakes, enhanced frozen brine, and recently, angel formula. also, recently, i've been using zoecon every week and zoe daily. any other suggestions for other foods i should feed to enhance color and growth?