current is always good for fish. if you ever go swimming/fishing in a river/lake. take note the current....in nature they don't sit in dead calm water. arowana are very strong fish too...also a power head can be used to increase oxygen by tipping it upwards, way better than use air pumps. the bubbles from air pumps is not the "oxygen" in the water, the oxygen is created when those bubbles disturb the surface water...so the more surface distrubance, the better oxygen.