Yes they can, in fact, the minimum tank size is 55 gallons
Wow didnt know this, I read they get like 16 inches and I thought there was no way. I'm assuming no tank mates? I hear they're semi aggressive and big anyway for the 75.I would say 75 is a good minimum. They probably will stay 8-10 inches in aquariums and 18 inch tank gives enough room to turn. Gouramis aren’t the fastest or most powerful swimmers either.