It looks like a healthy wound to me
I think you could just try to keep the tank in optimal condition and feed him lots of live foods and veggies! He should recover on his own
As the wound is healing, the edges should be turning gradually from red to pink to white. It's such a small wound, that I don't think you need to stress him by moving him to a quarantine tank.
If you notice that he's getting lethargic or otherwise worse, you should quarantine him and treat with salt and hydrogen peroxide on the wound (more info here: (Link is not visible to guests. Please register to view.
However, he looks strong and healthy otherwise, so I bet he'll just heal it on his own