10 Gallon Tank Betta fish’s tail shredded overnight

Hi everyone! This is my first post on here so apologies for any mistakes
My betta lives in a 10 gallon with 2 little cory catfish and they get along great except for catfish feeding time but that’s a separate issue. I’m almost certain that from one day to the next, the betta’s tail fin got shredded somehow. A significant chunk is missing. He swims around energetically and follows me around the tank if I’m near. I’ve read about all the possible causes but how do I know for sure?

Ammonia 0
Nitrites 0
Nitrates 10 - cleaning tomorrow

 

Is your filter intake covered? The plastic plants in your tank or hardscape could have caused it. Best thing for healing is clean water, I recommend increasing your WCs while he heals.

 

Hey just for the future cories need groups of 6 plus and a 20 gallon long minimum

 

You can also add some Indian Almond leaves to the tank for the tannins, if you can stand the sight of tinted brown water. The tannins will help with healing and will help with stress, too.

 

Is your filter intake covered? The plastic plants in your tank or hardscape could have caused it. Best thing for healing is clean water, I recommend increasing your WCs while he heals.

I can’t tell if I’m paranoid or if it’s getting worse each day.

 

It will take a little while for you to see a difference. When his tail has new growth, it may look translucent. This is normal. After a while, it will color again.

Hang in there! With clean water, and good care, it will get better!

 

I’ll hang in there! Thank you!