It would I suppose but the fish would not be nearly as content as in a 300g. Keep in mind they surpass 2ft, the tank is only 2ft deep. It would be nice to provide them with a larger home. If you have a 180g there are MANY other awesome fish that would love to live in a 6x2x2 tank.
Ive got a 20" Silver in a 6x4x2 (4 wide) and hes got lots of turning room and im planning to upgrade in a few years, it works out around 350 gal. No way id keep one in a 90, no more than 6 months.