Your pet looks natural to me! (assuming it's the one on your profile) Could you possibly be mistaking it for silver because the color for a winter Feiron is pretty similar to silver? Feirons have different color schemes for Spring, Summer, Fall, and Winter. The natural Feiron on the creatu species page I believe is the Summer variant.

silver baby feiron

winter baby feiron

spring baby feiron

fall baby feiron

summer baby feiron