Goldfish in the Livestock Water Trough

I started keeping goldfish in my water trough about four years ago. I currently have the same four fish who started out as quite small 9¢ in my 100-gallon stock tank, and another two goldfish in my 35-gallon sheep stock tank. The fish overwinter well in the troughs, especially because they have the added comfort of a submerged trough heater in the winter time. The fish require no supplemental feed; they eat the mosquito larvae on the top of the water, and also eat the bits of hay and forage that fall from the horses' mouths when they drink.

Because my Clydesales are so large and require 35 gallons of water each per day, and I also have five sheep to one 35-gallon tank, I'm refilling water troughs constantly. The continuous refilling generates clean water full of bubbles--and the animals only add more as they play with their water before they drink. The fish get the aeration they need, the food they require, and a large tank for swimming all while keeping our mosquito population down.

​Do the horses ever eat the fish? No--they swim to the bottom when the horses approach. Do any other animals or birds of prey hunt the fish? Nope--not once here on our farm. How do I know they're healthy and thriving? My vet friend says as long as they're eating, creating manure, growing, and swimming they're doing great.