It is based on food and space given. I doubt you'll grow it to 10 inches in a 50 gallon no matter how much food you give it. You'll need at least 100 gallon tank to do that.
I hope that you are getting a bigger tank. Mine is 12" long and that is the same width as your 55 gallon tank. They are stocky so they need a wider tank. I've had mine for about 7 years and he was already about 6" when we got him. I can't say how long it took him to get up to that size, but someone said it all depends on how much and how often you feed it.
That is him in my avatar. He is in a 125 gallon tank.