hi there.. Perhaps the salt solution will work. i will try it..
Here is a picture taken at the first stage. i will post more pic by next week.
Thanks for the remarks. BTW i notice another fish have a very strange shape of it scale.
I almost like these scales are eaten off. Any advise on this too.
I place all three arowana is a same tank but separate with glass partition . I will upload all this pic next week.