Interesting.I typically start to see color at around the 1.5" mark. The problem with big box stores, though, is that a lot of times the vendor that they get them from gives them a bunch of hormones in their food to grow them faster. This also has the added effect of making them color up quick and making females color like males. I have personally purchased box store fish that presented tons of color, when purchased, only to end up being female and losing all that color after a few months of normal food.
WowI typically start to see color at around the 1.5" mark. The problem with big box stores, though, is that a lot of times the vendor that they get them from gives them a bunch of hormones in their food to grow them faster. This also has the added effect of making them color up quick and making females color like males. I have personally purchased box store fish that presented tons of color, when purchased, only to end up being female and losing all that color after a few months of normal food.