You can use aspen instead of sand, as it will be easier to keep the tank clean. A water bowl will good enough for water/moisture. He/she will eat any kind of fish, goldfish, minnows, etc. Just float them in the water bowl. If you plan on letting him go, I wouldn't bother switching to pinks-- at that size, fish are good enough (or the occasional tadpole or small toad/frog)
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