Yes it looks like it. It could be a number of things. Likely it is low water quality sparked by a GF producing large amounts of ammonia and eating lots of food which can create more ammonia from uneaten food.
GF have issues like Septicemia more often because of often being in a too small tank, inadequate filter and uncycled filter.
People, so often, just don't really understand what is needed to take care of them. Sales associates often are undertrained or just don't have the resources to know enough to give proper advice.
There are gram positive and gram negative bacteria which can be killed by certain types of meds and usually a med will treat /kill one type but not the other.
Septicemia diseases are most that I know gram negative. There are a couple very serious infections so make sure to follow all the directions on the meds and do the maximun number of days the meds list to make sure there is the most chance possible for the bacteria to ALL be killed and not leave any stronger ones alive to just reinfect the fish.
Marycin 2 treats gram neg. Kanaplex.
What is the water temp?
Add an air bubbler to get the oxygen increased .
Clean the tank. Vac the substrate and get out any muck.
Get Prime water changing conditioner.
What are the gallons of your tank and how many GF of how many inches are in there?
Do you know about cycling the tank and the nitrification process? Is your tank cycled? Please check out the article from Aquarium Advice, getting started, in my signature.
