After I did a my water change I fed my fish and I noticed my Gourami has what looks like several small pin holes in his head on both sides. Could this be hole in the head disease? He isn't acting any different than normal. I have to admit that I have been neglecting my tanks lately(been busy with school) and I tested the water and noticed that the nitrate is very high. I plan on doing 20% water changes every day until I get the nitrate down to normal and I also bought a medication to put in the water to treat hole in the head, it has metronidazole as the active ingredient. Has anyone heard of this in a gourami? How long until I see improvement? Should I worry about the other fish in the tank?