Ulcer, I Think

[savo318]

one of my paradise fish has died, it started as small red marks on its side, they got a little bigger but the fish semed fine, swimming eating it was fine, ive got home just and found the fish almost dead, and with a large open sore where the red marks were. does anyone know what it is , and will affect the others. buy the way the water tests come back fine. and i did a water change three days ago.

 

[WILDER]

Its bacterial some water changes on the tank for a few days.
What are your stats in ammonia,nitrite,nitrate,and ph.

http/www.fishtanksandponds.info/care-mai...septicaemia.htm