Thank you for your advice. It was caused by my wave maker. I have them off for 5 days already and all their fins are coming back.
Thats good news. Like I said before, if the fins do not start to heal within 2-3 days most probably its fin rot. But honestly I never encountered the situation that a wavemaker causes frayed fins, but I only have Asian Arowanas...could be different to Silver Arowanas...
