Ulcers/Sores: Need help determining cause and treatment

Hi folks.
So to sum it up:

Main concern: Red sore/ulcer and possible scale loss on swordtails previously treated for ich. Timid behavior (has been since day one). Eating well. Pooping. No clamped fins. I've only owned the fish since January 9.

Water parameters (i use test strips):

ammonia 0ppm
nitrite 0ppm
nitrate 0-20ppm
chlorine 0
gh 150
kh 40
ph 7

Tank specifics (This is a quarantine tank):
10 gallon
Bare bottom
Sponge filter
97 gph internal filter
84*F
aquarium salt 1T/5G





thanks for your time and advice.

red sore:

possible scale loss around head? hard for me to judge:

Hi there, when you say you've only owned the fish for 8 days do you mean it came from someone else's tank or from a shop?

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Came from a shop. Okay I admit it was walmart. Normally I avoid their entire fish section like the plague but thought the black swordtails were cool. I already had a cycled but empty QT tank so figured I'd take the risk and get them. (There are 2 platies in this tank as well bought at the same time/place.)

I say it's probably something bacterial. Don't feel bad about getting fish from Walmart, I've done it too, the temptation was just too much. And strangely it was the only place I could ever find Paradise Gouramis. Try Melafix with the aquarium salt. Also you can try increasing the dosage of salt which will further kill off bacteria. If things don't start healing up you could use the Tetra life guard tablets. Do water changes every few days.

thanks for the advice! Melafix wasn't in stock at the local store and I didn't want to wait 2 days for amazon prime, so i went with the Lifeguard first. Yesterday was first dose and today the ulcer on the one fish looks less red and raised. Thankfully everyone was still eating and acting normally despite their appearance so I think these walmart fish still have a pretty good prognosis. *knock on wood*