finrot in my new betta?

Hi, I'm new to the fish-keeping hobby and recently got my first betta fish in my 10 gallon tank around 6 days ago. The tank was fully cycled before I added him, and I had a low flow filter and a heater going at 26°c. I noticed that he had sone rips on a few of his fins, but I assumed it to be nothing major and I also assumed that he had already recovered from finrot, since there were no discolourations around his fins. (if this had been the cause of his rips)

In the past 3 days, I noticed that his caudal and pelvic fins were pretty badly ripped and have now become twisted. he seems to swim fine and he's still eating, but I wonder if this is fin rot or a problem with the water or something else??

immediately upon finding this I did about a 50-60% water change and got rid of any tank decorations that might have been corrupting his fins. That was 2 days ago, and today I did an additional 20-30%
I have been checking my water every day and it currently reads:

Nitrate: 20 ppm
Nitrite: 0 ppm
pH: 7
KH:80
GH:60

These reading have stayed consistent since when I first got him. If this is finrot, I've heard aquarium salt is the best way to sterilise water and encourage new growth. How true is this?

I forgot to mention the first photo is him now, the second attached photo was when I first got him 6 days ago.

Can you please answer the following questions.

How big is the tank?
Has it got a heater? What is it set to?
Has it got a filter?
How strong is the current?
Is it cycled?
How often do you change water?
How much water do you change?
Do you vacuum the substrate?
What additives or chemicals do you use? Eg De Chlorinator?
Do you use tap or bottled water? If bottled water please give us the brand.
Do you have a water test kit?
Can you tell us the readings for ammonia, nitrite and nitrate?
When you clean the tank can you tell us exactly what you do.
What do you feed him? how much? how often?
Any tank mates? What sort how many?
How long have you had the Betta?
Has he got a history of illness?
Any plants or decorations? Please give details?
Can you provide a close up photo of the fish?
Can you provide a photo of the tank?

Clamped/ twisted fins are usually caused by protozoan or bacterial infections.

Try doing a 75% water change and gravel clean the substrate each day for a week.

You can try increasing the temperature to 30C for 2 weeks. If it's protozoan the high temperature will kill off the parasites.

If it's no better after that then use a broad spectrum fish medication but try the water changes and high temperature first.

Colin_T said:

Clamped/ twisted fins are usually caused by protozoan or bacterial infections.

Try doing a 75% water change and gravel clean the substrate each day for a week.

You can try increasing the temperature to 30C for 2 weeks. If it's protozoan the high temperature will kill off the parasites.

If it's no better after that then use a broad spectrum fish medication but try the water changes and high temperature first.

Click to expand...

big thanks, I'll try this out.