big goby has a red mark....pics

[queenbee]

noticed this today on my marbled sand goby.it is not a burn(no heater) water test out fine,it looks like it may be bumpy.i picked up some maracyn-two i think it may be septicemia,i also raised the salinity.i have had this fish for 9 years so any advice is needed!

 

[guppy]

I can't tell if it is septicemia, though that usually also shows streaking at the base of the fins, treating with the Maracyn 2 won't hurt though. It might be something as simple as abrasions.