so we've heard of red cap orandas, but yellow cap bettas? that's a first. here's another messed up looking betta that they are trying to sell. but hey at least it's not grossly priced. no pun intended. lol.

http://www.aquabid.com/cgi-bin/auction/auc...shmp&1207283628

i just want to pop it's pimple. it's white head. :P

oh and he calls it his April Fool's day bid. LOL. :OO

Looks like lymphocystis. I feel sorry for a buyer hoping to start a new thing. It's eventually going to go away and that little betta will be just a yellow betta. It's rather interesting that that growth is actually just one cell! I've seen lymphocystis get bigger than a golf ball on larger species of fish like northern pike. Here's a link about it.
http://www.aquarticles.com/articles/manage...mphocystis.html

Here's a link to a bunch of pictures of it.

http://images.google.com/images?q=lymphocy...18&sa=N&ndsp=18

I emailed the seller and told him what it was and gave him some links to learn about it. Seeing he already has this virus in his water he's bound to end up seeing it again. It's actually not that uncommon in natural bodies of water world wide. It even occurs in saltwater species.