my silver arowana is about 6inches, just bought him 3 weeks ago but he doesnt act like all the other arowana's that ive seen. you know how arowana's usually swim from one end of the tank to the other, well he only swims on one side of the tank and sometimes i catch him just laying at the bottom, even if i drop food on the other side of the tank, he wont go for it unless i tap on the glass and make him go over there, im afraid he's gonna get drop eye if he keeps being lazy...no other tankmates btw. anyone have any idea why he is acting like this?