Largemouth Bass with Fin-Rot

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jonhenderson10401

Feeder Fish
Aug 20, 2025
2
1
3
23
West Virginia, United States
Have you tested your water?
Yes
If yes, what is your ammonia?
0ppm
If yes, what is your nitrite?
0ppm
If yes, what is your nitrate?
0ppm
If I did not test my water...
  1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.
Do you do water changes?
Yes
What percentage of water do you change?
31-40%
How frequently do you change your water?
Every week
If I do not change my water...
  1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.
So this largemouth bass (Tony) has fin rot that started with/from a split on one of its pelvic fins. The first day is noticed was on August 16 and today is August 20. I dosed Melacure 10mL (per the directions) the day before yesterday, skipped yesterday (not per the directions), and dosed 10 mL today too. I also dosed 8.32 mL (0.5625 tbsp) of Jungle’s aquarium salt with the initial dose of Melacure. Tony is about 2.25” in a 10 gallon. He’s lethargic, while normally very adamant about being fed. He’s sitting on the bottom of the tank almost as if he’s “resting,” as the pictures show. And he’s now VERY skiddish to my presence.
Before anything being said about the tank’s volume, I have a 65 gallon that I’m waiting on GE1200 to be delivered for me to reseal it (about 7-10 days). I believe that is a factor, but I mainly attribute it to being bullied, the stress from me disturbing the tank to catch and remove the bully (bristlenose plecostomus), and low pH. Another stressor would’ve been that I had left the lights on fully through a single night to keep the bully at bay because he’d attack Tony as soon as the light turned off.
I believe I’ll just have to let Tony adjust to the change in environment, but with that said, I believe the solution to my low pH is to remove some of the driftwood. I’ve added baking soda before (no more than 1/4 tsp) and the driftwood wood just overpowers it. My KH stays at 2° and my pH won’t go above 6.8, it usually stays around 6.6. All Nitrogen is 0ppm.
-Now, what do I do in regard to the driftwood? I don’t think I should remove it, but I’m worried about the off-chance of a pH drop/fluctuation.
-What do I do for treatment? I believe that Erythromycin and Jungle’s fungal treatment is a better choice over Melacure. I just don’t know if I should finish the Melacure or not because I believe the fin-rot’s progression could be attributed to me skipping yesterday’s dose.
-What should I do to start dosing the antibiotic and anti-fungal? My first thought was to do a 25%-30% water change, then add the medicine. I just don’t know if I should add the salt back, and I don’t know if I should dose one of or both of the medicines.

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So this largemouth bass (Tony) has fin rot that started with/from a split on one of its pelvic fins. The first day is noticed was on August 16 and today is August 20. I dosed Melacure 10mL (per the directions) the day before yesterday, skipped yesterday (not per the directions), and dosed 10 mL today too. I also dosed 8.32 mL (0.5625 tbsp) of Jungle’s aquarium salt with the initial dose of Melacure. Tony is about 2.25” in a 10 gallon. He’s lethargic, while normally very adamant about being fed. He’s sitting on the bottom of the tank almost as if he’s “resting,” as the pictures show. And he’s now VERY skiddish to my presence.
Before anything being said about the tank’s volume, I have a 65 gallon that I’m waiting on GE1200 to be delivered for me to reseal it (about 7-10 days). I believe that is a factor, but I mainly attribute it to being bullied, the stress from me disturbing the tank to catch and remove the bully (bristlenose plecostomus), and low pH. Another stressor would’ve been that I had left the lights on fully through a single night to keep the bully at bay because he’d attack Tony as soon as the light turned off.
I believe I’ll just have to let Tony adjust to the change in environment, but with that said, I believe the solution to my low pH is to remove some of the driftwood. I’ve added baking soda before (no more than 1/4 tsp) and the driftwood wood just overpowers it. My KH stays at 2° and my pH won’t go above 6.8, it usually stays around 6.6. All Nitrogen is 0ppm.
-Now, what do I do in regard to the driftwood? I don’t think I should remove it, but I’m worried about the off-chance of a pH drop/fluctuation.
-What do I do for treatment? I believe that Erythromycin and Jungle’s fungal treatment is a better choice over Melacure. I just don’t know if I should finish the Melacure or not because I believe the fin-rot’s progression could be attributed to me skipping yesterday’s dose.
-What should I do to start dosing the antibiotic and anti-fungal? My first thought was to do a 25%-30% water change, then add the medicine. I just don’t know if I should add the salt back, and I don’t know if I should dose one of or both of the medicines.

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View attachment 1565720
Welcome aboard
The largemouth bass fins look like they are healing. How long has the aquarium been up and running. I'm asking because you should have a positive reading for Nitrate.
 
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Welcome aboard
The largemouth bass fins look like they are healing. How long has the aquarium been up and running. I'm asking because you should have a positive reading for Nitrate.
I’ll be honest, I didn’t test it. I did a 30% water change and dosed Kanaplex a few hours ago, or I’d test nitrates now. I have so many plants and I’ve kept fish for so long that I can almost guarantee it’s the lowest score on the API test. I think 0-5ppm? It’s been up and running for about 2-3 months. At the time of the OP, his fins looked worse than the day before, the fin-rot seems to be progressing. Hopefully the Kanaplex works, fingers crossed!
 
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