Injured / sick black moor goldfish
I have had a black moor goldfish since September. He is in a 10g tank alone with filtration. I do 20% water changes weekly and all of my levels remain good. I know the tank is on the smaller side for a goldfish which is why he is housed alone.
In the past few days, one of his iris's has become cloudy, he is resting on the bottom of the tank, mouth gulping, not eating. I called a local (very trusted, specialize in fish) pet store. They think it is an eye injury because it's cloudy only in one eye. They recommended adding aquarium salt and letting him relax. I did that about 24 hours ago, but haven't seen any change.
Does anyone have any recommendations or other thoughts about what the issue could be? It breaks my heart to think he is suffering.