angelfish growth

[joelaughing]

I've had an angelfish for about 9 months now and i'm not sure it is growing right. My friend has an angelfish that is 6 inches or so and it grew to that size pretty fast. Mine is probably a little less than half that size and i've had him for some time. So i guess my question is why he isnt growing or if he could be a certain breed that doesnt grow as large as the others.
thanks

 

[JeremyD]

genetics
temperature
stocking density
food
etc etc

All these will effect growth rate.