There was so many mistakes I made beside my water pH was little low compare to previous owner
Big changes in aquarium after I put him in
Stress from my arowana
Turning on lights when he already in stress
1. Stress hormones released into the bloodstream cause an increase in heart-rate and an increase in blood flow to the gills.
2. The increased blood flow to the gills results in the dilation of blood vessels in the gills.
3. As the blood vessels in the gills dilate the surface area of the gills is expanded.
4. The expanded gill surface causes an increased influx of ions and water loss in saltwater fish. Conversely, freshwater fish experience an increased influx of water and loss of ions.
Adrenaline disturbs ion transport at the gill membrane, and both adrenaline and cortisol cause temporary changes in gill permeability which, in fresh water, results in dilution of the blood by excessive gain of water. Avoid handling your fish at all cost. Spooking or stressing the fish, such as tapping on the glass or playful nibbles from tankmates, will cause this surge in adrenaline.( Info available on this site)
That's what happening to him stress from tank mate and many other stupid mistakes I did which eventually results into expanding gill and heavy breathing and death , I am ashamed, guilty and because of my mistakes he loose life I turn happy and healthy fish into dead body in 3 days !