If u want to grow a huge tilapia in that pond add one tilapia and a couple other fish such as stonecats and sunfish,don't add another tilapia until perhaps 4 or 5 years pass.what about for small 275g indoor pond? i've seen tilapia bred in them
Nile tilapia tend to grow bigger than most other tilapia varieties.
If u want my opinion for a 275 gal I would go with the following stock: 1 Nile tilapia,1 redear sunfish and 1 brown bullhead and a fair amount of baitfish such as golden shiners