Hard to tell from that pic - need to see the guy with all his fins fluffed up and displaying. It "could" be a sailfin, but that would mean his fin is not only high, but also very long. "high fin" describes a shorter but verticle top fin.
i'm not going to even try to ID the guy from that pic - you'll have to search the hard way - but looking at that pattern, I doubt he's going to grow up to be less than a foot long, but it could take him another year to get there, so don't panic just yet.
Correct ID is important in the long term to make sure he's getting the right diet, so keep at it until you know for sure. If you get any better pics, run them up.