This situation may be that the arowana has not adapted to the environment when it first entered the fish tank. It will get better after a while. If it has adapted to the environment, then we need to treat it by changing the light. It is best if the light outside the tank is lower than inside the tank, for example The light outside is very strong during the day, so we need to turn on the internal lights to make them stronger than the outside light.

Tips:

When there is no light at night, we don't need to turn on the internal lights, so it will get better after a period of adjustment.