Tetra Color Fish Food?

I've always given this to my fish. All my fish seem to like it. But my baby platies wouldn't eat it when they were a week old or two. So I gave them Hikari First Bite food. Then after they got a bit bigger they wouldn't eat it. Then I tried crushed Tetra Color flakes, and they like that stuff. So why did that happen? And what are your opinions on the Tetra Color fish food?