With all those fish, it'll keep your water cloudy longer as well. In addition to stirring up the sand, they all make waste, assume 1gal per inch of fish, more for goldies they make more mess. And more for fancies because they are more fat and less long, so 2gal per inch at least.
On the plus side, your tank will cycle quickly.

Though it will get toxic with ammonia first, keep an eye on that.
If it's really so cloudy that you can't see anything at all, you may want to start over. Empty the tank, take the sand out and rinse it really good again. If you're setting up a smaller tank anyway, you can keep your turtle warm in there while you're working.