I have 4 Roseline Sharks in my 75 gallon tank. Yes I know I should have at least 6 and do plan on getting more when everyone is healthy again. 3 of the 4 are totally fine and happy, but one has been slowly fading in color over the past week or so. Behaviorally he's fine - he's eating and swimming just fine, no gasping or anything either. Just the super faded color. I feed a mix of flakes, pellets, freeze dried shrimp, and fresh veggies.
I have treated the tank with a sodium chloride/malachite green mix as well as an antibiotic, but nothing seems to have helped. I was going to do a anti-fungal treatment next, but wanted to see if anyone had ideas of what could be causing this so I'm not subjecting my fish to unnecessary treatments.
I have other fish as well and the one lone Roseline is the only showing issues.
dGH - 10
PH - 7
Nitrite - 0 ppm
Nitrate - 20 ppm
Ammonia - 0 ppm
Temp - 78