I have been fly fishing nearly all my life. The author clearly knows a great deal about the topic and gets all of the small details correct. There are many things that are obviously planted in the show which are specifically for the fly fishing enthusiast. Each episode so far has had a moment that has left me amazed that a fellow cute anime girl enjoyer also knows as much about fly fishing as I do. A similar anime I liked was Houkago Teibo Nisshi, however, Slow Loop is more detailed than that was and gives fan service to the avid fisherman more (in lots of subtle ways).
This is truly "literally me" the anime.
I highly recommend picking this up if you enjoy fishing.