i did some reading online and came up with this....
"Head-rot Syndrome
This is a very unique syndrome affecting more on Asian Arowanas then its Australian and South America couterpart, it is also more common in younger arowanas. In this syndrome, the head of the fish start to get oedematous(swollen) followed by a layer peeling off from the skin, starting from the front of the head and moving backward. Activated carbon is believe to be the cause due to its close association with the syndrome. It is thought that activated carbon removed vital element in the water and hence disallow the head tissue to form normally. Other hypothesis around include irriation by the microscopic carbon particle deposite on the head. Healing is usually complete and occur withing days when carbon is removed. Zeolite product could cause similar problem too but less severe and less common. Large arowana is less sensitive Head-rot Syndrome.. "
still not sure at all tho.. he ate fine and was swimming fine until this..
