Your not always getting what you pay for with the expensive brands, eg most of them have t,u,v,w,x,u & z to fill them out, but many also have vitamins etc. On the other hand I occasionally buy a supermarket pet brand flake that has krill as its major ingredient without the soybean meal + x, y ,z that I have zilch idea what they are but no vitamins. I also use veggies, frozen bloodworms and the odd live food, basically just like for us a good balanced diet is the key
KC
PS also take note if your fish eat it (try a few times first, they mey take some time to come round)