I have a 7x2x2 tank stocked with a large tropical gar, 3 endlis, and an ornate. A buddy of mine needs to rehome a silver aro. I know typically gar+silver fish is a no-no, but I also know my trop spends alot of time dogpiling with the endlis and at the bottom 1/3 of the tank.
The tank itself is going to be an issue eventually it sounds like, but the arowana/gar combo is unfortunately too unpredictable to give a good answer. I would say the majority of people have problems with it and thus I would say don't risk it. It can, however, be done. If you really care for your trop though then you may not want to risk it. In a 2 foot wide tank the possibility of damage to snout/spine from a spook into the glass is big. Arowana's tend to steal food from gar leading to very spastic behavior from both fish...
they will eventually have an 8x4x4, just not at the size to need it yet and I didn't want to undertake such a large endeavor if not certain we would be in this house for the super long term as it would have to be built in my fishroom.
I figured it would be iffy, only reason i was even considering it is because the trop eats massivore off the bottom, never a surface eater at all. I would not want to risk his health though as he is probably my favorite fish.
I have no experience with aros, let alone gars and aros...but I have stocked a tank with 3 wild Florida gars and 2 large golden shiners (and other natives), and to this day it isn't a problem. It probably depends on the gar in question and what it eats.
i have not had problems with my fl and aros...since you have the tanks to do it i would...i have always had aros with my fl and i am going to be adding another silver, a black,(when they wont get eatten) and a few more gar and aros down the line...i plan to get around 10 more gar to add right now..
