how does it take gill curl to heal after its been trimmed off

[ampz]

i was planing to buy an arowna that recently
had gill curl its it inches the guy trimmed it off
already.now i was wondering if it will happen again

 

[classic-chassis]

It will only happen again if water is not clean, if the tank is too small and the fish can't turn properly or if there is a large, quick flux in water temp like on a water change.
I trimmed the soft membrane off my fish 2 weeks ago and it's started to grow back already. Looking like is going the right way as well.