From my notes it looks like my tank had nothing but diseases but then I realized that I only wrote something in the log book when something happened, like a disease. I rarely wrote anything if nothing was happening as I have months in between logging anything. In the very beginning it was all diseases because the fish all came on the verge of croaking. The stores would throw out all their fish in the first few days if they didn't sell because they died anyway. Eventually we figured it out and kept copper pennies in the water to control parasites.