They grow pretty slow. mine grew about an inch per year. I threw him in a koi pond and he grew about 6" in 8 months. I guess all the algae really helped. They dont do well with their own kin and will usually fight with themselves. If your going to put it in with your dats, make sure they are a decent size compared to your fei feng. Fei feng are notorious for eating body slime off other fish