First off, let me say I am new to the site and so if there is a fish injury thread already open and I simply haven't found it, my apologies.

So, I have a tequila sunrise guppy male that I noticed began hanging out a lot by itself at the top of the tank. Upon closer examination, I noticed a small open wound just before his tail fin on the bottom edge of his body. It doesn't appear to be a fungal infection etc, but most likely a simple wound of some sort.
He appears to be fully capable of moving and eating, so I am not too worried, but I would like some opinions on how long this will take to heal if I begin treating with something like melafix.

For anyone curious, my tank chemical readings are all within acceptable ranges, and there are several other guppies in the tank (29 gallons). There is also a clown pleco, 3 hatchetfish, and 2 quarter sized angelfish.