My Question is when did fighting bettas become illegal in Thailand? As far as I am aware both fish, mantis,cricket, and cock fighting are all still legal there. It is the gambling that is legally frowned upon, mainly because it is hard for the government to get thier cut.
I will not debate the morality of these practices but will point out that out of the four listed only in the betta fights do the losers generally survive to fight another day. Traditional Betta fights continue only until submission, not death.
Now, to answer the origional question on training fighting bettas I refer the thread originator to the following site maintained by someone who breeds, raises and fights thier fish. Go to
www.siamaquatic.com. There is quite a bit of info available there.
If you must actually fight your fish make sure you get the right strain for it, the show type longfins are totally unsuitable.
$5 for a good plaket is a pretty good price.