clamp fins?

[double oh nine]

i currently have 6 juvies discus in my 55 gallon. its been 4 days since they've been in the tank. i notice just yesterday that a few of them has a clamp fin. one is its pectoral fin is clamp, but it only happens when its stationary. only then it happens off and on.

i read in another post to try to turn the water flow down. this seems to work and his fin doesnt clamp up

are the fish still getting use to the tank? any ideas please help.