i've got a little 5 inch motoro. he's got a 55 gallon all to himself for now. (i tried a baby arrowana for a tank mate, but i should have let it grow out. the ray broke the little guys tail, probably because he was close to food-size, so try to stay away from tiny aros.) there is only white marine sand on the bottom, no aquascaping because he seems to enjoy the open space. i've thought of driftwood also, but he digs around in the sand so much itd be pointless to try plants. possibly with different substratethey wouldnt get uprooted...?