the 55 doesnt have all those fish in it still it actually has been depleted alot...he is in a small breeder tank till he grows big enough to fit in th 55 withouth problems..
So... you have an arowana, and a jag, and the largest tank you have right now is a 55 gallon? Do you still have that RTC? Even if you got rid of the rtc, you'd still need to do some serious upgrading.