My betta is quite old, and in the past 3-4 months his health has declined rapidly. His eyes are cloudy, though he seems to see large/dark/close-up objects. His back fin has rotted away completely and there is a white fleshy mound on his back. He hasn't eaten in almost a week, even when I drop a pellet right in front of his mouth. Increasingly he sinks to the bottom of his tank and lies on his side.
Is there anything I can do for him? Or is he just at the end of his life?
Other info: (I'm sorry I don't have all the information. I had no idea there were so many ways to better monitor my betta! He's mostly just done his own thing for years.)
What size is your tank? 2.5 gallons
What temperature is your tank? Ranges from 70 to 80 degrees F.
Does your tank have a filter? No.
Does your tank have an air stone or other type of aeration? No.
Is your tank heated? No, though it sits under a light which warms it.
What tank mates does your betta fish live with? None.
What type of food do you feed your betta fish? Pellets.
How often do you feed your betta fish? Almost every day.
How often do you perform a water change? Once or twice a week.
What percentage of the water do you change when you perform a water change? 95%
What type of additives do you add to the water when you perform a water change? "Betta Water Conditioner" and "BettaFix Medication."
Have you tested your water? No.
Symptoms and Treatment
How has your betta fish's appearance changed? Slightly duller colors, but mostly still brightly colored. Cloudy eyes. Back fin has rotted away.
How has your betta fish's behavior changed? Listless, doesn't swim around much anymore, rarely extends his frills and gets angry, not eating, can't seem to control fins very well.
When did you start noticing the symptoms? About 4 months ago.
Have you started treating your fish? If so, how? No.
Does your fish have any history of being ill? No.
How old is your fish (approximately)? About 6 years old.
Thank you in advance for any advice!