I would first like to say that this problem resolved itself. I was giving my convict cichlid a steamed pea, and looked over at my ten gal and though that maybe my little female betta would want some. So I gave her a tinyyy piece - like 1/4 of a pea - and I held on to the tiny tip of it and lowered it into the water. She a couple bites, and then for reasons I have no idea why, her right gill started bleeding. She wasn't acting unusual at all, still swimming around acting like the typical fatty she is, and after about 5 mins the bleeding stopped. I'm still stumped on what could've caused that, maybe my fingernails, which aren't long at all, could've nicked her when she lunged at the pea. Idk.