my silver arowana used to be afraid of my hand. now it attacks my hand every chance it gets. it has a large swimming area, i keep it well fed, and i provide decorations and plants to keep it happy. starting yesterday it bit my hand every time i put it into the water. i didnt think it was a problem but now everytime i enter the room, it starts swimming very actively and tries to swim through the glass to get at me. after feeding time, i reached over to close the tank lid and it jumped out of the water and chomped on my finger. it hung there for a few seconds and dropped back into the water. i was too stunned to move. why is it suddenly so agressive? 
