Hmmm, that's a mighty fishy story. I assume this fish has legs that it uses when it walks out of the lake to devour the horses. :o) I don't think horses walk deep enough into the water for a big "monster" to grab it.
Your wrong there, friend.
We had an old mare that loved to go decided to go for a swin. Unfortunately we were riding her once on a very hot day when she headed to the deep end of the pond and rolled over spilling us kids into the water. Luckily we knew how to swim at that age.