Its a funny thing with goldfish colors, even more so in babies. They change all the time, and with a calico in the mix you never know. Most babies have somewhat of a dark color as baby color, and it will subside as they grow. Is it a deep velvety black, or a more subtle brownish color?
Wen take a while to develop, and it can take up to a year to see if it really has one or not. My babies had almost no wen for a long time, and that little thing they finally developed was basically a laugh...