I'm thinking about african cichlids. It will be nice for my kids to be snorkeling and looking at the blues, yellows, etc. This will also help keep the mosquito population down which I'm sure my neighbors wouldn't appreciate. I just ordered some Peacock Bass which should be coming in a couple weeks. I'm planning on letting them grow to around 7 inches or so then putting them in there. I'm also giving the pool/pond time to mature. I would hate for something to happen to them because I jumped the gun. I also want to see what kind of readings I get in my water with 7 square meters of rock in my filter. I tried volcanic red rock and its working great in my 3,000 gal pond but it has a lot of red dust in it and its almost impossible to get out. With this big pond I'm thinking about ease of cleaning and there will be plently of dust settleing in the bog area already from the wind. I don't want to add any more. Usually with these swimming ponds they have the water circulating down through the rock. For me it makes more sense to push clean water up through the rock to be filtered by the plants, then over the retaining wall to the swimming area and then to the bottom drains to the filter. Feel free to give advice if you all feel differently.