I have two bettas in a ten gallon divided tank, they used to be in a divided 5 gallon tank but that didn't seem nearly big enough to me, so I upped it. My male is in heaven, he's never seemed happier. My female on the other hand... She seems frantic and well, the only way I can think to describe it is zoomy. She zips back and forth all day, at first I thought maybe the male was stressing her out somehow even though the divider is opague so I put up some really big leaves to block it but nope. Then I thought maybe her air stone was putting out too much current so I removed it but nope. Then I thought well maybe I wasn't feeding her enough so I upped her portions a bit because she does zoomy zoom all around when she's hungry and she had grown quite a bit but again, nope. (also now I think I done overfed her because she looks a little bloated to me.)
Now on top of everything else it looks like she's been biting her own fins or tearing them on something but I have no idea what would tear her fins as I've sanded every decoration in their tanks to be baby smooth. I don't have her old 5 gallon available anymore but I have no clue what could be causing this or what I should do about it. I have no idea what could be causing her stress because literally the only thing that's changed in her enviroment in the tank size. She has been zoomy and hyperactive ever since the size upgrade but the fin and tail tearing is very recent.
Should I get her a smaller tank and just give my male the whole ten gallon? If I do will he get super stressed too? (though he is absolutely massive, about 5.5 inches when fully flared so I don't think he'd mind but what do I know)
Is anything even wrong? I'm just comparing her behavior to my male as he's the only betta I've ever had, but my male one super chill fish so who knows (Back in their old tank the female jumped onto his side once and he could not have cared less. Just chilled in his cave till I noticed and scooped her out). I'm considering moving her to a hospital tank while I treat her for these fin tears but the only one I have available is actually bigger than what she has now and I'm worried that if she is getting stressed from too much space that won't help at all. So currently, because of that, they're both getting a healthy dose of bettafix. The male as I said is absolutely massive, so he does get the occasional fin tear as well so I don't think a dose of bettafix would do him any harm.
Also: She looks positively ragged and I have no idea why. A couple of days after I got her, she started developing black patches of scales all over her body. The scales are still there, they're just jet black. She had a little patch on her forehead when I first got her and then that just got bigger as she did and more patches popped up on her sides. I was really, really worried at first but she eats fine, and is the exact opposite of lethargic, also they're nearly perfectly symmetrical on both sides of her so I think it might just be natural coloring but I have no idea and no amount of googling has turned up any diseases with symptoms like that. (black patches on her body but not fins and super hyperactive)
Any advice is appreciated, I'm absolutely terrified that I'm an awful fish owner and have doomed my female to a horrible fate or something. I had a baby betta that was kind of shoved on me by circumstance but I was scared I'd accidentally kill him so I gave him to a betta breeder guy I met on craigslist who swore up and down he'd take good care of the little dude. Should I do the same for my girl?
Details:
Nitrates: 0
ammonia: 0
Nitrates: 15 ppm
tank: 10 gallon divided
I have 2 preset heaters in there, one on each side because it gets really cold in my room and they like to hang out right next to their respective heaters when that happens.
I have a mini submersible 10 gallon filter set on low flow and angled upwards on the female side, causes little to no currant really, less than the one I had on the 2.5 even. And a sponge filter on the male side. Female had an air-stone but I removed it just in case.
a couple of live plants but they're not new. Just a java fern, an amazon sword and moss balls. Both bettas have had live plants in their tanks since the beginning.
Also have a couple of almond leaves in there.