I had Orandas for years, in Ohio, where I didn't have to worry about water temperatures being too warm. I'm now in Maui and have a 30g freshwater aquarium (gouramis, neons, etc.) and the water temperature stays about 78. I worried that's too warm for Orandas. I'd like to get a second tank and I see that you can get "chillers" for salt-water aquariums. Anybody have any experience using these for Oranda, Fancy Goldfish, etc.? What's the optimal temperature for Orandas?