Growth rate of any cichlid (including all pikes) is highly influenced by your water change routine.
If you do a large water change once per week, it will grow slower than if you do 2 changes per week, or faster if you doo 3 per week.
So trying to define growth rates is subject to the energy of the keeper.
In nature in rivers like the Xingu, these fish are in constant 100% water change, with average rainfall in that part of the would, the Xingu river discharge is about 72 million gallons per day.