Legendary fish help

So I was looking behind the massive waterfall and it gave me a notification for the legendary fish and I thought it would be pretty badass if I climbed on top of the big rock in front of the waterfall and fished little did I know this would be the biggest fish I've ever seen in the game and it tells me I have to stow it on my horse so here I am looking on this ledge thinking how to get my fish any help? (Ps i stumbled across a black bear and currently have its perfect pelt on my white arabian named SACRIFICE!!! rn.)