unless you measure him you may not notice how much he has grown. One thing I use to do is take one side of the aquarium where it is not too visible and put a ruler up to the glass and make tik marks every half inch. Then it was much easier to notice fish growth. Just an idea. Your's should have grown at least 1/2 inch per month, especially if eating shrimp every other day. How much do you feed when you do feed him?