The information on that eBay page is only partly correct:
The Nile puffer t.fahaka or t. lineatus is considered the most aggressive freshwater puffer of all, in most cases they must be kept with no tankmates at all- including other nile puffers. Aggresion increases with age.
Most Nile Puffers will attack and kill anyhing that moves in the tank, and in some cases will even try to attack people outside the tank by ramming the glass.
Ours shares a tank with a large common plec, but she is well fed and unusually docile, even so, she has twice taken neat semi-circular chunks out of his fins (now healed)
They get to 18 inches very quickly, (ours has grown six inches in three months), need a large tank (6 feet) with perfect clean freshwater with heavy filtration and regular large water changes, and a daily diet of hearty,shelled foods such as prawns, shrimp, cockles, mussels and snails.
Ours also loves mealworms, mealworm pupae and jumbo bloodworm.
Are you prepared to devote a six foot tank to just one fish? If not, don't get a nile puffer.