I am thinking of digging a small pond directly above and eventually feeding into my main pond. The ground is red clay under about 8 inches of topsoil. The goal is raising fathead minnows for forage and bait. I am thinking 20 feet across and about four feet deep with a capacity of about 9,000 to 10,000 gallons. This is in NW Arkansas. I am thinking an adequate (screened) water supply could be provided from the main pond and a nearby intermittent creek. Is this big enough to raise several pounds of minnows per year?

One can get FHM to spawn in a aquarium so you will get spawns. Aeration and fertility (feeding) will determine your production amount. Keep us advised in this thread about your success. You might want to consider adding some crayfish to help control the algae/weeds. Crays may suppress (turbidity)some plankton production but feeding ground pellets will help compensate.

Crayfish (we call them crawdads) naturally populate ponds in this vicinity. They migrate on warm rainy nights.

John, glad to see that someone else calls the mud bugs crawdads.

We finished the minnow pond this morning. It will be about 42 feet long and 27 feet wide (oval) at what I expect to be normal pool, with a good bit of the center at a depth of 3.5 feet. Capacity at this level is about 14,000 gallons. At full pool, it will be about 52x40 feet and 50 inches deep with extensive shallows. How many fathead minnows can I expect to raise during the warmer months of mid March through October? Should initial stocking be about two pounds? Can't stock until fish truck gets to our vicinity in mid to late February. I don't have any way to aerate, although in an emergency I could circulate water with a gas powered pump.

I envy you John! I can offer this from my experience, I threw 300 (about 1 pound) FHM in a 1/4 acre pond with no predators in the spring of 2014. By August I had tens of thousands if not more. IMO make sure they have spawning habitat and maybe toss in some squished up pellets once they get going if the pond is not fertile enough to support the herd. Please let us know you results.

Would some untreated floating boards or an old plastic tarp floating make suitable spawning substrate?

FHM will spawn under just about any submerged or near shore floating object.

Here is a picture of the minnow pond with the main pond in the background.