I have 6 Cardinal Tetra's in my 20 gallon community tank. Have had them for about 3 or 4 months without any issues. The tank is fully established and has been running for about 5 months now. I water change 25% of the water every week. Today I came home and noticed a white spot on 1 of the 6 Tetra's and I'm not too sure what it is. I have a pictured attached if anyone can please help to identify this and what I should do.
Thank you.
Thank you.