A slow current. Any fish that likes a slow-medium current please tell me. I'm not sure if this helps, but there won't be nearly any plants, except floating ones. The tank will have lots of bogwood and rocks as well as being bare bottomed. I would appreciate schooling fish and catfish native to the Amazon more than any other type also.
Here are a few suggestions, although the fish are not all from Amazon region. Try looking at some of the Tetra genus, or Barb genus of fish, or maybe some Rasbora fish. These fish enjoy a river type flow, but not a raging rapids experience, just a gentle flow. As with all species of fish, you will have to research them fully
