FYI HSB will do fine on high protein food. It is not required but will not hurt. What is important is the total feed profile sources of protein , carbs and lipids + micro-nutrients etc. They need to be close to matching the fishes natural diet.

I will be glad to send someone my power point presentation on Fish nutrition if they will somehow post it here. I guess the individual slides could be made into a slide show and posted. That is beyond my computer pay grade however.