I'm the exact same way. I'm sure it drives my parents up a wall though
It kills me to leave a suffering animal, so matter what kind.
We've rescued a few dogs and found them great homes (Kept some, got too attached. (: )
And while at walmart I saw a pleco with a hurt fin. It looked broken and tattered. So I had to get him. With a bit of love and medicine his fin is perfectly normal now. I also saw a male betta- fin rot. Who could say no?
I got him and have had him for about a year. Sadly now, he's gotten a tumor..
I also saw a little female betta, not even in an inch of water. She was laying sideways in her cup, if she sat normal her mouth would be out of the water. I couldn't resist, yet again. Now, queen of her own 20 gallon tank.
I'm sorry to hear about your fishes fin. I'm no fin expert, so I'm really not sure what caused it.
Good luck with your fish (: