I recently got some chingmix headbooster for my flowrhorns who have a HUGE appetite. They don't seem to be liking it and spit it right out. I have been feeding Hikari cichlid gold for a staple. Omega one color flakes, freeze dried bloodworms, and mysis shrimp for treats. Do I need to fast them for a day or two to get them to accept the headbooster or is there a betterway to do it?