Hello everyone! I have been keeping fish for over 20 years, but this is only my second attempt at summer tubbing. Last year, I had a planted whiskey barrel guppy pond, and they did great and had lots of babies! I have recently fallen in love with Medaka/Japanese Ricefish, and have been reading and watching everything I can about them for months! They are supposed to be hardy, adaptable, and perfect for ponds and container gardens. We dug a 30 gallon pond at the beginning of April, put plants, rocks, and driftwood in. We added beneficial bacteria, and dechlorinator, and left it be for about a month. In the meantime, I got a school of beautiful platinum ricefish, quarantined them with meds, and observed them closely for several more weeks. They were doing great and the female even had eggs! A few days ago, I introduced all 8 ricefish to the pond. I acclimated them slowly by pouring pond water into their container of tank water, over the course of an hour. I sat by the pond for the next few days watching them swim happily and gobble mosquito larvae! They were so beautiful! Then, on the 3rd day...disaster! Only 1 medaka came up to greet me yesterday morning. I found the rest dead in the bottom of the pond, and assume the last one has died as well. I was heartbroken! I buried them in the garden and tested the water. 1ppm ammonia, 0 Ni, 0 Na. I didn't think water changes were necessary in ponds/summer tubs, but do I need to do them? What do I do to fix this problem? Or do I just wait...and test every week? When is it safe to try again? I really thought ricefish were super hardy and could tolerate most anything. I am shocked and devastated to loose all of them. They were showing no signs of distress. I really want to try ricefish again, but I won't put all of them outdoors next time (or all of my eggs in one basket). I thought my pond would be ready for fish by now. Please help?! Thank you!