Hello,
Well with my experience, remember that there are many things that come into play with ANY fish growth rate; the two main being diet( I use NLS and Hikari) and water chemistry(including frequent water changes, I did and still do weekly). You'll be able to start sexing the fish at around 2in. Males will most often have hints of blue along the jawline. It'll take about 4 months for some good size and color.
I had a Red and an OB reach a full 6in in about a year.
Well with my experience, remember that there are many things that come into play with ANY fish growth rate; the two main being diet( I use NLS and Hikari) and water chemistry(including frequent water changes, I did and still do weekly). You'll be able to start sexing the fish at around 2in. Males will most often have hints of blue along the jawline. It'll take about 4 months for some good size and color.
I had a Red and an OB reach a full 6in in about a year.