My fish suddenly (seemingly overnight) developed a red sore / blister on his anal fin. I'm having a difficult time remedying this and can't seem to find any solid information on the internet about this problem. If you have any experience with this problem please let me know. I appreciate any and all suggestions. I'll include a picture in the following post. Thank you!
Housing
What size is your tank? 2.5 gallons
What temperature is your tank? 78 - 80 Fahrenheit
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes, I have a 25-watt heater.
What tank mates does your betta fish live with? No other tank mates.
Food
What type of food do you feed your betta fish? Nutrafin Max flakes. Approximately two times a month I supplement his diet with live brine shrimp for a few days.
How often do you feed your betta fish? Twice a day.
Maintenance
How often do you perform a water change? Every five - seven days.
What percentage of the water do you change when you perform a water change? 100%
What type of additives do you add to the water when you perform a water change? API Stress Coat & Nutrafin Biological Aquarium Supplement (helps reduce ammonia and nitrates)
Symptoms and Treatment
How has your betta fish's appearance changed? Sudden development of a large red sore / blister on anal fin. This has since turned black (looks like it could be dead skin tissue).
How has your betta fish's behavior changed? He seems slightly lethargic, occasionally sitting on the bottom of the tank. He has also stopped blowing bubble nests which he used to do quite frequently. His appetite has not changed.
When did you start noticing the symptoms? Around two weeks ago, the red blister seemed to appear overnight.
Have you started treating your fish? If so, how?
Initially (when I thought this was fin rot) I added aquarium salt to the tank water at appropriate intervals. Later, when I spotted the red blister I stopped using aquarium salt and medicated him with a product by a company named 'Waterlife' for fin rot & ulcers. It was a myxazin solution and I used the appropriate amount for the correct period of time (five days). I didn't see a great deal of improvement. It has since been a week and the red blister has turned black. I don't know if this is due to the efficacy of the medicine or if it can be attributed to time having passed.
I went to an aquarium shop and showed the owner a picture of my fish (I live in Hong Kong). He suggested I use a product made by Aqua Gem called Fungus Proof Water Treatment. It is made by a UK company and says "it's effective for: mycotic ulcer, erythrodermitis, fin, gill, mouth rot and prevents fungus diseases". I don't know what type of medicine this is and there are no 'ingredients' listed.
The first medicine I used was for baterial infections, the one I'm thinking of using is for fungal. Do you think I should try this medicine? I'm wary of over medicating my fish.
Does your fish have any history of being ill? No
How old is your fish (approximately)? One and a half years
