I would like to know if there are any tangs I could keep in a 55 gallon tank. I was planning on having a stronger water current to make up for the space in the tank. I have not set up this tank yet just thinking about it.
Not really. The closest option would be one of the bristletooth species but those could really use another 25+ gallons of swim space. By the time you fill a 55 with rock, there just isn't much room for a tang. You'll get a lot of opinions on this wherever you look but just seeing how these fish behave in the wild should tell you they need more room than a 55 will offer. If you want a broder body fish, I would suggest looking into the Dwraf angels.