Purple "lump" On Betta

[LyraGuppi]

Pearl has a purple swelling on her side. I hope to upload some pics soon.
 
None of the other bettas have any problems, it's just her.
She was acting fine all day yesterday and earlier today, but now she's having troubles swimming. It's like her tail is floating, she swims with her head down.

 

[starlitsunrise]

Pearl has a purple swelling on her side. I hope to upload some pics soon.
 
None of the other bettas have any problems, it's just her.
She was acting fine all day yesterday and earlier today, but now she's having troubles swimming. It's like her tail is floating, she swims with her head down.

Could it be something wrong with her swim bladder? I don't have first hand experience with this but I found this website and reading the swim bladder section sounds like what your describing: http/www.bettatalk.com/betta_diseases.htm . They say on the page that it is not contagious so that might be why only one of your bettas is acting strange (if it is an issue with her swim bladder). 

My sister had a female betta named Pearl years ago and I loved that little fish, I hope your Pearl feels better soon. 

 

[AshleyNZ]

If she's having trouble with her buoyancy, it could be related to swim bladder issues. Most people would suggest a deshelled pea, split into halves. The issue could go away overtime. 
However, a purple swelling on the side...does not sound good. Unfortunately I cannot help too much without pictures. 

 

[Wildbetta]

Without pictures it would be hard to be sure what the issue is.  I would suggest at least one side view and one top view to show the lump.  Her swimming sounds like something is bothering the swim bladder like previously mentioned.  Although in this case it sounds like whatever the lump is might be what is causing her swim bladder issue.  It is most likely a tumor or cyst. 

 

[LyraGuppi]

That's what I was thinking. I have the pics ready, I just need to upload them.

 

[LyraGuppi]

SIDE:

I left them big for observation:
 
TOP:

 

[Wildbetta]

Hrm well in the first pic I would have at first glance thought it was just coloring.  But seeing it from the top view makes it very apparent that it is not.  It is in the area of the swim bladder which is probably what is causing her swimming difficulties. 
 
Do you have any idea about how long it took for the lump to get to this size?  Has she always had a spot of color there or is this new with the lump?
 
I do not like the coloration with the lump.  While it is not "red" like you would see with bleeding, the first thing I thought of was a bruise on any other creature which would be not a good thing for such a small creature.  It very well could be from a fighting injury with one of the other girls in the tank.
 
At this point, I would recommend removing her from the main tank to watch it without the other bettas possibly making the issue worse.

 

[LyraGuppi]

Hrm well in the first pic I would have at first glance thought it was just coloring.  But seeing it from the top view makes it very apparent that it is not.  It is in the area of the swim bladder which is probably what is causing her swimming difficulties. 
She's not having much trouble, just a bit.
 
Do you have any idea about how long it took for the lump to get to this size?  Has she always had a spot of color there or is this new with the lump?
New. I noticed the lump on Monday, and it was the about the same size.
 
I do not like the coloration with the lump.  While it is not "red" like you would see with bleeding, the first thing I thought of was a bruise on any other creature which would be not a good thing for such a small creature.  It very well could be from a fighting injury with one of the other girls in the tank.
 
At this point, I would recommend removing her from the main tank to watch it without the other bettas possibly making the issue worse.
I'll try setting up a rubbermaid hospital tank. This sorority tank is gonna give me a complex! How long do you think she should stay out? And another question, how could I switch the stocking of this tank? Would I wait for all the ladies to die, (That sounded better in my mind XD) and then build the stocking back up slowly?

 

[LyraGuppi]

The swelling down a bit, and she's acting better. No swimming problems.

 

[Wildbetta]

That is good news.  Maybe it was just a bruise from a scuffle between the girls.  However that does mean you will need to monitor the tank a bit more to watch out for aggressive behavior between the girls.

 

[LyraGuppi]

I'm hoping to add caves in in a few days.