No that really is incorrect. These are huge fish. They need the extra space to move. Just because someone kept these fish in smaller tanks does not mean that these fish are okay in small tanks. They will stunt easily in a 30 gallon and in a 55. Please look into larger tanks.
Seriouslyfish says 60inx24in is about okay for a single, which means you should add extra inches to both sides. A 55 gallon is 48x18-24.