Lemon tetra injury/disease ID

[Finding NiMo]

20G long, A-0, Nitrite- 0, Nitrate- 10, pH 7.8

9 cardinal tetra, 7 lemon tetra, 4 pygmy cory, 1 GBR

White hazy spot developed in flank of one of my lemons. A few males have been jostling and flashing a lot lately, but don't see one or the other being targeted. 

Not sure if this is injury or infection?

Thanks for the help

NM

 

[Colu]

Looks like a growth in the muscle tissue possible a cyst it could also be a benign or cancerous growth if you have quarantine tank I would more it and treat with maracyn2 active ingredient minocycline also has anti-inflammatory properties and aquarium salt 1 table spoon for 2 gallons just remember to only put back in what you take out so if you do a 2 gallon water change put 1 table spoon of salt back in as salt only removed though water changes if after a week there's no improvement more than a cancerous or benign growth there's not a lot treatment wise I could recommend for that other than monitor