Well, I'm actually Dutch, living in Asia since '98 and in Thailand since 2005.
Personally not much into trading fish or knowing any traders.
Can tell you that 99% of the traders/breeders here are into following categories: Koi, Arowana, Flowerheads, Discus.. Especially Discus are very popular due to the soft water straight out of the ground.
Many of the breeders have some side programs with other species, but will be some work to find specific Poly breeders.
You might want to check with Pete, (User name: NolaPete). He's looking into importing fish again, used to do it before.
He asked me for help if necessary, which I could do without problem, being on the ground, might make for better shipments and quality.
Anyhow, not much of help for now, sorry..but give a pm to Pete and see if he can help you in the right direction.
Cheers,
Luc