Mine were 17-18" in length and they just made the aro more agressive at feeding time.
You won't believe this but i actually gave them away because they were out growing my 220 gal and nobody wanted them. The guy i gave them to had them spawn in his pond the next day.....dam it. They ate pellets, shrimp, frozen fish. you learn pretty fast when they get big you wont want to feed them feeders any more as the wave of water flies out of your tank and your tank starts rocking back and forth.