Yes you can can keep an arowana in a pond (need to cover it) alot of people here do and i will also have a aro/ray pond after the first of the year. If the pond is big enoght you can keep those fish with the aro but keep in mind u will need a big pond
its 7ft 6" long 5ft wide and 3ft deep will be running a cloverleaf cl3 pond filter which is rated for a pond of approx 3500 gallons so should be ok and a coil denitrator.
thought this would be ok size wise for a while anyway if need to be bigger will have to save me pennies up LOL
just make sure your aros and pacus are big already, because of couse rtcs get huge, so if you have sud-adult or adult fish and you get a small rtc than it should be ok. or else the red tailed cat will eat any thing as big or smaller than it, especially a nice long skinny aro, YUM! Good luck and Merry Christmas.
will try polycarb sheeting then as its reasonable priced over here know what you mean about rtc it ate both of my giant gourami`sone was about 8 inches the other about 6 inches didn`t realise just how big their mouths are the pacu`s are ok as there about 10 inches so well to big the red can fit an ocean stick in its mouth sideways and its only about 15 - 16 inches long!
hopefully the coil deninatrator wil be good we`ll see as our water down here is 100 ppm before i even put it in the tank and its a massive one so should be ok