I wasn't really sure what to name this but ok.. Aaaaanannnnnnyyyyywaaayyy  My idea is that when nichlings grow up their patterns change slightly in some way or form. In real life some animals lose their patterns, or get larger ones when they mature. For example, a fawn losing its spots when it gets older. Perhaps this could be integrated into niche? Although maybe not losing their pattern Completely because that would be kinda annoying if you have a really pretty nichling...