badflash - I seemed to have done everything in reverse on this. I put the fish in the system with no plants, then added my grow medium killing all of my fish. Well let that cycle for a little to let the dust settle then added more fish. I have about 5-6 goldies left, but they obviously aren't providing enough nutrients to the system. Unfortunately, I already have plants in the beds and I am keeping them alive with daily dosages of MaxiCrop w/ Iron, unless those goldies are producing too. So I want to step up to tilapia and hope to pick some fingerlings up this weekend. Do you suggest then 50 fingerlings for the time being and pull them out as they grow and take up to much space? 25 2 pound fish in a 55 barrel drum seems excessive, but then again I am new to this.