Hi, I'm trying to put as much detail here as possible, so thank you in advance for reading.
My betta has a lump at the start of his dorsal fin (picture HERE
--sorry for the blurriness but it's hard to get a decent photo).
I was out of the country for 1 month and had someone else watching him. This person fed him and replaced the evaporated water, and also performed two 50-75% water changes while I was gone. I came back and the fish had this lump. He is also lethargic, doesn't swim around much at all (especially compared to how he used to), tends to lie at the bottom of the aquarium. I immediately assumed it was some kind of bacterial infection.
The tank is 10 gallons, heated (kept around 77 degrees), filtered. He currently has no tank mates. He eats 6-8 betta bites once per day. I perform weekly/one-and-one-half-week 75% water changes but have been doing them more frequently since I came back and noticed his condition (discussed below in treatment). I use AquaSafe to cleanse the water.
Now, here is the real problem, treatments I've tried:
- After getting back (~1 month ago) I changed ALL of the water in the tank and cleaned the tank pretty thoroughly (multiple rinses with clean water, scrubbed the sides of the tank, used soap on both tank and accessories while scrubbing and rinsed thoroughly afterwards). New filter. Within about 2-3 days I started to get paranoid and decided it would be best to hit it hard because it looks so terrible, and bought Meracyn Two. I started the treatment as instructed and stuck with it for 14 days but stopped because I saw absolutely no change. I had 24 packets of the treatment, and instructions say the treatment should only have to last 7 days--I tried two rounds of it with no success. For the first round I had him in the 10 gallon tank. For the second round I quarantined him in a 5 gallon tank (no filter but heated). Neither of these had any effect whatsoever.
- After this failed I started doing bi-weekly water changes (~75%) but this doesn't seem to have helped either.
Quick note: about a month before I left I did have a severe/persistent dark green algae problem but it looked like it was cleared up (I did a lot of cleaning) before I left the country. It doesn't look like there's any green algae in the tank now.
I am very, very concerned now because the part of his dorsal fin closest to the lump appears to be wilting away to the spines now and he is more lethargic than ever.
I am considering putting him back in the 5% tank, heated, with filter (?) and changing the water every single day until I start to see improvement.
Please let me know if this is a good idea or if you have any other suggestions. Thank you so much for your replies.