To tame a Shadowmane, approach it stealthily while it slumbers, ideally in a Ghillie Suit or after consuming Cactus Broth. Provide it with a Filled Fish Basket containing a fish of a minimum size of 0.5x. The species and level of the fish are inconsequential. Keep in mind that fish sizes in ARK can be misleading due to rounding; for instance, a 1.5-sized fish might range from 1.45 to 1.54. Given this variance, ensure you have additional fish on hand. As of now, the exact timing for this process remains unverified.

Passive: You need to tame it while the Shadowmane is awake.