Adding minnows to your pond will help keep it clean and natural. While minnows will become part of your pond's ecosystem, you still will need to provide some minimal care to keep your minnows happy and thriving. By preparing the pond to suit their needs and by keeping them healthy in the beginning, you will be able to insure that your minnows thrive over time.
Make sure your pond is properly aerated. Whether it is an air stone hooked up to a pump, a fountain that circulates water, or a little activated waterfall, you need one of these ways to keep oxygen in the water.
Check your pond depth and temperature. Pond minnows are not going to tolerate high water temperatures. The water must either be fairly deep, in the 4 foot range, or shaded for a considerable amount of time during the heat of the summer. Shallow sunlit ponds are deathtraps for pond minnows.
Feed your minnows about once a week. You can feed them regular goldfish food. While pond minnows will eat insects or larva that use your pond to breed in as well as the algae that grows on the rocks or the sides, they may still be hungry even after they have made your pond sparkling clean. Give them a little extra to tide them over about once a week.
Be on guard for herons. A heron can clean out a pond, and they often target residential ponds because they know that they are full of fat little fish. You can use shiny objects to frighten these birds away from your pond.