I wouldn't add goldfish, or any fish. I tried a small pond that was in the ground and the water got too hot for mosquitofish which can take warmer water than goldfish. Being completely above ground even in the shade I'd expect the water temp to be way too high. With the dark color and 50% in the sun the water might be too hot even for plants, or maybe some plants. I've been growing Canna and some kind of Umbrella Plant like Cyperus alternifolius and a nutsedge (purple I think) in soil in containers with no drainage, so standing water but normally below the soil level. That mimics how I keep marginal plants in a pond which grow best not submerged. The sun, heat and humidity are hard on these. These are all pretty much in the ground, but the further up out of the ground the least well they do. I've repotted plants that have been in the sun and the soil is much too hot for me to touch. I've been experimenting with different sun exposure. Canna barely survive full sun. Morning sun seems to be best, til 10 am. Enough sun to bloom, not too much to stunt them. So I don't really have any tips for what you're wanting. If you want a water feature I suggest you just do that. Then add plants for the cooler months, or if some make it thru the summer then great (let me know what). Maybe something like a pondless feature. 5 gal bucket with holes goes contains a small pump, kept up off the bottom by a brick. Then fill with rocks/stone around the bucket. At the very top you can add a more expensive rock for looks. Add water so it stays below the rocks. The fountain hits the rocks and sinks back down to the pump. Plants can be placed in the gravel/rocks either bare root or the whole pot with soil. But you have to make sure the water level stays up to at least say 6" from the top. A fountain might be hard on most plants which don't like to be covered in water. And you could get lime deposits on leaves. Because there's no standing water you don't have to deal with string algae or mosquito larva. I've had container ponds other places, NY, FL, CA, and none of that applies in Phoenix. I used to read gardening books and web sites and watch gardening TV shows, but don't any more...just doesn't apply to us.

Don't worry about it. Do the Hosta in China, Korea, and Japan have the streams turned off in August? I don't mean to be offensive. I have a tendancy to over pamper my hosta as much as the next person and have to keep reminding myself that this Genus of plants have been on this earth long before gardeners. (lol) Les

and it has, pretty quickly in fact. In just a few days the water has become nice and clear. There is still some muck that has settled back down to the bottom but nightly I go out and try to stir it up with a skimmer net. My hope is that eventually the bottom will be nice and clean.

it should clean itself out.