Sudden Red Sore On Neon Tetra

[nike12301]

In one of my tanks, I have a neon tetra whose developed a spot/sore on his side. It's a reddish/brown circle and looks just like a scab almost. He doesn't seem to be eating much either. I first noticed it after I had to take the fish out of the tank temporarily to do some maintenance. I'm hoping it's just stress from that, but it's been a couple days. Could this be some kind of sickness? I looked up neon tetra disease, and the spot doesn't seem to be white like the pictures they showed. Any suggestions? I've quarantined him, but don't know what else to do.

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite,nitrate, and ph.

You don't need to remove fish from tank to maintenance.
Any signs of flicking and rubbing, excess mucas, darting, erratic swimming, laboured breathing or gasping.

If none of them signs I would treat with a bacterial med.
Does your heater have a guard on it.

 

[nike12301]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite,nitrate, and ph.

You don't need to remove fish from tank to maintenance.
Any signs of flicking and rubbing, excess mucas, darting, erratic swimming, laboured breathing or gasping.

If none of them signs I would treat with a bacterial med.
Does your heater have a guard on it.

Water stats are all good. I checked yesteday.
It's a 10 gallon tank. He's in there with another tetra and a male betta or at least he was until I quarantined him. (I know, I know neons need to be in large groups. They're my survivors from a previous tank a long time back. I was actually planning on getting more but that day, the red sore popped up.)

The only other strange behavior I can notice is that his mouth seems to be constantly opening and closing. Maybe it's gasping but I thought that would be through the gills.

No guard on the heater.

Does Melafix/Primafix consitute a bacterial med? I've never used one before.

 

[WILDER]

You can use melafix and pimafix but don't know how good they are as never used them both together.
Some fish don't tolerate the full dose of melafix, so I would just half dose for now to see how he gets on.

is there plenty of aeration in the tank.
Fish can heavy breath with bacterial infections.