flagfins don't perch or hitch. they're quite good swimmers. i never had any trouble with any LPS or even a large tube 'nem.
what was pretty cool was the fact that my Janss' set up a cleaning station, and would use an odd vertical "see-saw" swimming motion to advertise. when the fish in the tank saw this, they'd line up to be groomed. this is more common in younger fish, but my adults did it as well.