I use a tweezers when pulling off parasites like Lernea.
sometimes the vector is so entrenched parts of the fish come with, I took part of the fin here
but you should make sure you get it all, and not leave a part in the fish, some will infect, some parasites have the ability to regenerate.
Most wild caught fish seem to carry a parasite or two. In nature they can be simply an irritant, but in the confines of a tank, they can easily get out of control as the young parasites reinfect over and over again in the small space