Found this on Buzzle.com
Pacu fish care becomes a herculean task when it comes to breeding them in aquariums. This is because of their huge size and prey hunting instincts. But commercially, they are a big success and are bred in massive fish tanks.
To breed pacu fish, the tanks must have a capacity to hold minimum 50 gallons of water for juveniles and at least 200 gallons of water for adults. The tank water must be filtered regularly and the temperature should be maintained between 23 - 28ºC. Also the pH balance of water must be maintained between 6.5 - 7 and the hardness up to 20 dH. It is recommended that fish tanks have enough hiding places as these fish have prey hunting habits. Juvenile pacu fish enjoys the company of other fish but as they mature, they tend to become solitary by nature. But generally, they have a mild temperament and get along well with other species like Oscar fish and Clown Knife fish. At times, pacu fish are also bred in indoor ponds.
Tonight I will see where I can find 50 or so of these. Any ideas please let me know.