I'm about to set up an outdoor goldfish above ground pond, since spring is here. Last year, a racoon or something (I'm pretty sure it was a racoon, because I saw it wandering around), ate my pond goldfish. I kept a ceramic planter sunk in the little 50 gallon pond for the fish to go into, but learned that is not enough. I've been told to use an open ended cylinder on the bottom so they can run in either side this year. I'll probably have a couple of comets and some rosey barbs and danios mixed in. They have all been able to overwinter well in Virginia. I keep a solar heater in it during the winter, and the ice still gets in it, but the barbs, danios and comets live. Did the same in Colorado with no heater, just a fountain, and the rosy barbs multiplied and lived over winter all without feeding for months during the ice. I was surprised about the rosy barbs.