I have a 50 gal tank with 3 goldfish. Goldeen, the one who is sick, is a golden fantail. the other two are a calico color and a black moor. They have been together probably 3+ years. I run a 110 Aquaclear filter system (HOB). The water readings are all fine. But is the pH is horrible! Not even a reading (off-scale) just the same color as putting drops in (yellowish) meaning extremely low.
Goldeen has developed some whiteness and shredding on her tail fins. Po, the black moor, looked alittle white around his eyes. Goldeen hasn't been eating well and kind of bloated but she's overweight anyway. Just kind of hanging around the bottom of the cave. Not herself at all! She is the food hog and tank bully normally.
I added some pH Up to the tank water but don't want to stress the fish out more. Or overdo it with medications ( I haven't had good luck with medicating in the past).
I added some new water about a week ago but it has turned cloudy and hasn't really come back to a decent clearness (we have horrible city water overdone with chemicals making it good for humans) even though my test numbers all look good except for pH. Today I also changed the carbon filter with the charcoal and added a filter that removes toxins and ammonia hoping to help the water quality.
What else can I do? I don't want to lose her she's part of my girls
What is it? Ich? Fin rot? What else can I do? Should I separate them or medicate the whole tank? Do a water change?