So a few weeks ago I found myself with an Oto and a male Betta sharing a planted five-gallon, because I did a stupid and listened to the pet store lady, and because the algae is getting ridiculous. I'm aware it's a bit crowded, I'm looking into possibly getting a 10-gallon, but it's going to be a while because of fund and room issues.
At first, my betta didn't seem to like him at all; would flare and chase him every time he moved, but never seemed to actually catch him much, and when he did, never seemed to connect or bite, so I left them to sort themselves out. Now they look to have settled into a sort of mutually antagonistic, somewhat peaceful cohabitation; The betta only chases the Oto about half the time, now. I think it's because the Oto is getting to be about his size.
My only question is this, twice now I've seen the Oto chase and try to feed off the betta's fins. Is he nipping? Can Otos even nip or is he just being irritating back to the betta for chasing him off the big algae patch on the log again? or is my tank just that saturated in algae that my betta is starting to grow it on his fins? (I've been changing the water weekly, I cut the photoperiod, I've been pulling a lot out, it's not a dirty tank, it's just ridiculous algae.)
My betta is getting some raged ends on two of his fins. I know it's not the filter this time, because it's set to barely a trickle, and there's no signs of fin rot that I can see, no grey or black or white, just a little clear new growth, so I'm thinking either he's stressed and biting his own fins or he's blowing his fins working himself up over the Oto.
My biggest problem is, if I absolutely cannot keep the Oto in there for whatever reason, I don't really have anywhere else to put him. I'm working on finding the time and money to throw into a larger tank, but it's not really something I can put on priority right now. I don't have any friends with tanks who could take him, and I'm hesitant about asking a pet store to take him; I've gotten kinda fond of the little guy.