I can’t tell if it’s a fungus disease, but he lost all of his color. My sister never cleaned his tank so I think that might be the reason behind it, but I don’t know what disease he has so I have no idea of treating it. I put him in a separate tank with clean water, will he just get better on his own? He won’t eat. 
![enter image description here](https://i.sstatic.net/Oldj5.jpg)![enter image description here](https://i.sstatic.net/NpjSq.jpg)