andywg
Bored into leaving
You'd need a lot more (around six times more ti be kind to the fish) than a 500 gallon tank before you can consider a fully grown RTC. They rarely get more than 3 - 3.5 feet in aquaria and locals tell stories of seeing them up to 8 feet long, though I don't know of any corraborated stories of the getting much more than 5 or 6 feet long.