Check the amount of protein in it anything over 45% min protein is good.
Also try to feed it some chopped up worms. Fish love those. Mine really likes market shrimp too.
They grow very fast. Mine grew over an inch a month from 1.5 to 7 inches now (approximate) I also have 3 babies 2 that are 2.5 inches and a 1.75 incher. They are all growing so fast you can damn near watch it happen. Vary their diet. For the young hikari sinking carnivore pellets seem to spur amazing growth also worms and chopped shrimp and silversides are my bichirs favorite. They all like beef heart as well not too sure about the nutrition on beef heart however.