first gigas get WAY to big do you know what there name means it means GIANT and they would need a tank atleast 10' wide and 30' long
next why would you only put a few catfish and knifes and aros in there thats a huge pond i would have a ton of fish in there second spounge filters don't work we'll with huge cats they do like to eat random stuff and you would need alot more filtration then that
aslo that tank/pond or whatever would way TONS a gallon wieghs 8 ponds 2500 gallons is about 20,000 pounds with the water alone thats more then your house (mabye not if your rich but you probly won't be able to keep it in your house)
also jars are pretty aggressive and will most likely get eaten silver aros are probly the only aro you could get and you would wan't a big one RTC grow FAST