Took my dovii about a year to get that big. New Life spectrum jumbo fish formula,krill,market shrimp and some barbs that he did not want in there with him. lol
If you 86 the pacu you can keep a dovii with two other aggresive tankmates in a 400 to 500 gallon tank. Grey who is a mod on a certain other fish site kept a 22" dovii with a 16"+ managuense and a 15" midas in 400 gallon tank.
For a single male dovii I would reccomend atleast a 180 gallon tank.