It would work for a little longer, but you're going to be looking at, bare minimum, a 180 for this guy. And, for big waste-producers, the standard is to go at least 8 to 10 times volume in flow -- so that's 1800 to 2000 gallons per hour, and at that size, pumps can be pricey. You'll need to switch over from canisters to a sump, most likely, which is more expense. Also, his adult size (and the size of his mouth LOL) are going to really limit what you can keep with him. Then there's how much he'll cost to feed and how much the salt is going to be needed to keep up with the regular, good-sized water changes that he'll need. He's just going to get big, and eat a lot, and poop a lot. This is all stuff to think about and decide if that's the direction you can go and want to go.