Mike Fin lives in a 1-gallon bowl with a silk-and-plastic plant and some rocks, which I rinsed and refilled with dechlorinated tap water about once every three days. I've had him for about 1.5 years; no idea how old he was before that because I got him from a sorority benefit sale.
About 10 days ago, he started showing signs of popeye (eye started to swell a bit) and had a white cottony patch growing near his mouth. He'd been lethargic for a few days before that, but since I've never had a fish before, I didn't read it as a sign of illness and just assumed he was tired.
I read up on the Internet, decided it was probably a water quality issue (small bowl), changed the water right away, and started treating the water with Melafix for the fungus at 1/2 tsp per 10 gallons of water once a day. I also did 100% water changes daily.
The popeye subsided after two days, but the white patch by his mouth remained and got bigger, covering most of the top of his mouth like a mustache. Yesterday, as Mike Fin was aiming for a piece of food, he somehow bumped the fungus on his mouth, and his entire top lip fell off.
As far as I can tell, he can no longer eat food because his mouth no longer closes. I watched him try and fail to grab a pellet about four times when I fed him tonight. :(
Now he's lethargic and just kind of floats around, either hanging out at the bottom of the bowl or on the plant. Sometimes he struggles up to the surface of the water and gasps at the air, but even when there are food pellets he usually doesn't even go in their direction.
I don't want Mike Fin to starve to death. Is it too late? What can I do?