Hello! I have two bettas. One is a female, and the other is a male. The female is perfectly fine, but the male is not. It seems that almost overnight his fins have become really shredded.
He usually lives in a ten gallon tank with a filter, heater, and two live java ferns (as well as a couple fake plants). It seems like his fins have always been a bit ragged at the ends, but they never got bad, and he didn't seem sick at all, so I didn't worry. However, I think he might have started fin biting. Friday afternoon I took the train and drove (a trip that, involving waiting for the train, took about eight and a half hours.) During that time he was kept in a tupperware container, and sloshed around a bit (I tried my best to keep him still, but with an armfull of luggage there's only so much you can do) When I finally got home, I took both of my bettas to my room and placed them in my empty ten gallon tank. The next day I bought two one gallon containers for temporary housing, because I am only going to be at my house for a week and I didn't want to completely set up two different tanks only to take them down again in a couple days.
In these one gallon containers I placed some hornwort from my mother's pond, as well as a couple rocks from the garden. I washed off the rocks and plants as best as I could before putting them in the tank.
They both seemed to be doing pretty well on Sunday and monday. However, today I noticed that my male betta's caudal fin was shredded pretty badly, and he was just sitting still. He could be sitting still because he's used to having a lot of space, but I'm worried about his fins. His pectoral and pelvic fin seem fine, and his dorsal fin and anal fin are only slightly shredded.
For water conditioner I used stress coat, the API brand that you can get at PetSmart.
I've also heard that excessive lighting can trigger stress. Is this true? There isn't any artificial light that filters into his tank(except for the lights on the tank) but the light is on for a pretty long time, and he gets indirect sunlight as well.
He's always been a bit prone to stress. When I first got him, he hid for the first two weeks, and did the same thing when I moved him to a bigger tank.
Now that I've written this novel of a post, I guess that it seems he is a fin biter, rather than having fin rot.
I guess my question is how to prevent it, and how to heal the already shredded fins. Also, would darkening his container when I brought him back help relieve some of his stress?
Here are some pictures, so you can better see what I am talking about.