Are you planning any filtration? If not it will eventually become smelly and annoying regardless of what you put or don't put in it. But yes, if it is sunny you could wait a week and then add fish. Without filtration I would not introduce anything larger than Gambusia (Mosquito fish).

Thanks so much for the response! I didn't realize there was a section here for ponds. Anyway, no I do not plan on using the pool's pump or filtration system. I want a completely natural pond setup. I read some of the other blogs and it doesn't seem much of an issue. I just was wondering what the opinion was of others on here.

I was reading that the Mosquito fish breed rapidly and will take over the entire pond, so I was thinking about introducing 5 Comet goldfish instead. And with the exception of many plants and manually skimming the surface of the water weekly, the only other treatment I'd would be adding a bi-monthly all-natural algae control.

Mosquito fish do breed pretty rapidly but they are fairly self sustaining and they tend to level off after a certain amount of time. The first year I had them I panicked about the numbers and removed a bunch of them throughout the summer. Didn't make a difference. Then after the fist year I just stopped paying attention and about 8 years later they are no more dense then they were that first year.