Betta split tail

[lordroad]

My prize golden betta has split tailfins.

No other fish is nipping on him, and it is not finrot. My best guess is he's flaring up too much at his reflection due to the backdrop. I've removed the backdrop and hopefully this will heal him back to himself.

If that's not it, could it be the current? I use a biowheel HOB, and the current is only strong enough to rotate the wheel enough to maintain moisture. The betta swims into the current and it looks to toss his tail around.

Ammonia, nitrites: 0
Nitrates: 15

The only fish that could conceivably chew on the betta is an oto, but I've never heard of that before.

 

[lordroad]

Oh wow, it's the oto. Just saw him chase the betta and zero in on the tail... has anyone seen this before?

 

[itchy armpits]

I think fish like Otos tend to suck on the slime coats of other fish when they don't get enough food.

I'd take the betta out for a little while, step up the feeding for the Oto, and then put him back in and see what happens.

I've had a betta in a 10 gallon with a AC mini, and no problems. The current seemed to push him around, but he liked to swim against the current. When I turned the filter off, he looked crappy (like he was back in the cup). The current tore his finnage a little bit, nothing bad though.