We have an aqua phonics system set up in the backyard with lots of fish in it. 13x 4 x 3.5 foot pond dug in the backyard with liner. We put lots of different size PVC pipe in for places to hide and have several different types of fish we caught - tilapia, blue gill, jack Dempsey - they've been in there for about 7 months and are surviving quite nicely. Recently we noticed that one of the larger t…