same as me for my first ever arowana an rtg i got quite long ago in 2003 when i first started my aro hobby.kept it for almost 2 yrs.i was still a newb so was changing water and the aro jumped i neglected the cover and it jumped out of the tank and hit the floor from a 4ft height.i changed 70 per cent of the water cuz i didnt know abt the water cycle yet.i quickly put it back into its tank and it was not swimming stable already couldnt maintain its swim posture had probably injured its spine due to the fall and jump.it still tried to swim but it had no energy and it began to float upwards.i lowered the water height to make it swim upright better and i placed a divider to position his body against the tank wall to stop him from overturning as overturning will kill the fish cuz it cant breathe when its overturned,i increase the aeration and added aquarium salt and oxycure.the results became worse after 2 days it was still alive but its scales were all redden and swollen,probably dued to the water condition as the new water caused pH shock to it too.the scales on its top dried out due to it floating above the water surface causing the scales to dry out.died on the 5th day.i hope yours will get thru it.make sure to check the water quality,increase the oxygen level in the tank and dun stress the fish out.but give it lots of attention.