Fin Tearing? Biting? Stress? Please Help.

Something is happening to my betta's fins, and I need help figuring out what's causing it. I don't think it's fin rot, but I would really appreciate your opinions. I've only had him for three weeks. This is what he looked like a few days ago:


Yesterday when I went to check on him, he had a small tear in his caudal fin:


I wasn't too concerned. I know betta fins can tear with use. But today I noticed more small tears:


I know they're small and virtually harmless, but I want to keep him healthy and happy. Any ideas what could be causing this? It doesn't look like fin rot or biting to me. Here's my tank set up:


I have a few rounded stones, a whisper filter, a heater, cardinal plants, amazon sword, crypt, anubias, and java fern. The substrate is fluval stratum. He flares at the two nerite snails a lot; could that be causing fin damage? Please help. Thank you!

 

Flaring does not cause fin damage. It doesn't really look like rot or biting to me, though it's hard to say 100% that it isn't rot because he has black fins.

The best treatment for fin damage is clean water. There is not a medication that will help with this- it's likely someone will recommend salt but in 30 years of keeping Bettas I have never seen it help and have seen it do harm (the same is true of meds with names ending in -fix as well as antibiotics). If that's a 5-gallon tank then I'd recommend 50% water changes every other day until you see healing.

 

Thanks for the advice! I just did a water change. If you have any ideas about how he could be tearing his fins please let me know!

 

Usually damage like that is mechanical- caused by something sharp in the tank- but as you have only live plants and smooth rocks, I didn't see the point of mentioning that. All I can suggest is that you watch him closely and see if he's doing anything like squeezing himself into a small space (going into a space likely won't hurt but coming out again can do). With my current Betta, for example, I had to glue filter floss to the back of my heater because he kept squeezing behind it and I was concerned he'd be hurt.

 

Usually damage like that is mechanical- caused by something sharp in the tank- but as you have only live plants and smooth rocks, I didn't see the point of mentioning that. All I can suggest is that you watch him closely and see if he's doing anything like squeezing himself into a small space (going into a space likely won't hurt but coming out again can do). With my current Betta, for example, I had to glue filter floss to the back of my heater because he kept squeezing behind it and I was concerned he'd be hurt.

Thanks for the tip!