Question about Chance's fins, please help!

[nochoramet]

I'm getting really worried about Chance's fins. Just in the past 2- 3 days his tail fin has become half the length it used to be. I don't know if it's fin rot because it's not like ragged and red looking, like Haze's fins were. It looks like someone just razored it off. And it keeps tearing up the length of his tail then it will disappear. He's acting normal but WHAT'S GOING ON???
Here are before and after pictures. Is it fin rot? Did it get sucked up into the filter and ripped up? Is he biting it? Gah I'm so worried...

[doggyhog]

Doesn't look like fin rot to me.... Does he have trouble swimming with the filter in his tank?

It's probably tail biting.. who's on the other side of the divider???

[1fish2fish]

It looks like he may be biting it.. the only way to know is to
1. catch him in the act
2. cover all filters with pantyhose and make sure nothing in his tank can tear his fins then see if it still happens.

[nochoramet]

Haze is on the other side. I just have 2 now, and they share a 10 gallon. Would tail biting show up just randomly that fast? I've had him since October, and he's never done it. It first showed up last Friday, I noticed his tail looked a little ragged so I took him out and put him in the little tank I have with some salt. When it looked like it healed back up I put him back in the 10g with Haze, and now his tail looks like this :[
What am I doing wrong?
Oh, and he seems to swim fine with the filter. I have 2, been debating on whether to take one out but I thought the more filtration, the better. I built baffles out of water bottles so there isn't as much current...

[1fish2fish]

He is probably stressed out by seeing the other male.. I've had this problem. Just put two pieces of plastic canvas in your divider so they can't see each other at all.

[doggyhog]

What happened to Libby?

My tail biter all the sudden started to bite his tail once I put him in a divided tank with another male. Put him next to a girl, all flirty no bitey!

[nochoramet]

My friend fell in love with her and begged me for her sooo... I let her take Libby. She's got 2 other bettas so she's not someone who mistreats them. I just wanted 2 fish for now. Should I take Chance out and put him in his own tank?

[nochoramet]

Ok so I'm taking one of Vikki's fish because she needs to find homes for them. For now, I put 2 pieces of plastic mesh in the divider instead of 1. Would this make it better? Or should I take Chance out and put him in the little tank. Or should I buy a girl anyways, and put her in between the 2 guys? Hmmm decisions, decisions.

[doggyhog]

I think it would be best to put one of Vikki's fish in the divided tank and put Chance in his own tank. :) He'd probably like that best.

[nochoramet]

Ok :] I'll just let Haze have the whole 10g right now, and put Chance in the 2.5g. Kinda feel bad though haha Haze will get the mansion for now!