I'm not an expert, but I'd let it go awhile before putting anything in it. We've had some decent rain lately, but it was just a few months ago that many peoples stock tanks/ponds went bone dry. And there are plenty of people who have dug holes in the ground thinking it would be a good tank only to find out the soil won't hold water. A friend of mine has a few tanks dug on his 100 acres. At one time they all held water, but over time they have dried up due to the soil and drought. It would stink to stock it with fish only to have it dry up and the fish die.