Sick Algae Eater?

[somethingfishy]

I looked at my algae eater the other day and noticed that he had some weird black spots on his tail. They were scattered on just the back fin, and no where else. ALthough a few days later I noticed that some of the scales near his back fin where black-rimmed (he is a gold algae eater). Could this be a bacterial disease...or something else? And if so, how do I treat it?
Thanks,
somethingfishy

 

[WILDER]

Black spot is easy to cure, you will have to buy a med for black spot.