Sorry, should have been hey lady, apologies.
Hey Lady, I think you'll be outta luck, I mean that is an immense tank the length and width are amazing (6 feet, correct?) but damn its short,
From a quick bit of research " The current world record largemouth bass weighed 22 pounds 4 ounce and was 32 inches in length and 29 inches in girth"
So even if he get to most of that size, he wont fit. He will stick out the top of the water by a number of inches. Either go with a skinnier fish, (but long) (You are in the states? I think you can legally have an arowana) or get one and upgrade your tank accordingly when required. Typically aquarium fish don't get AS large as their wild counterparts, so you may never need the upgrade. But.... better to plan for it just in case IMHO.
Good luck,