Blobthingy On Female Betta's Vent...

Hello.

My betta has had this white blob on her ventral area.  Sometimes it's there and sometimes its not. I haven't seen her pooping and she's bloated.

  Her behaviour is normal, she has 4 tankmates- a baby bristlenose and 3 neon tetras.
I've also been dealing with Neon Tetra Disease, which is why I only have 3 neons.
None of the other fish have it. I will post pictures when I get a couple.
Any ideas would be very helpful.   

http://www.bettafish.com/attachment.php?attachmentid=413490&stc=1&d=1408051134

http://www.bettafish.com/attachment.php?attachmentid=413498&stc=1&d=1408051189

http://www.bettafish.com/attachment.php?attachmentid=413506&stc=1&d=1408051243

Hmm....

All I can think of is an internal parasite but none of the other fish have it.