When I was younger, used to go fishing with my dad, he had an employer (kepala) a malay who work as the head of the logging camp. He gave me a young toman found in Pekan Pahang area. He told me this is Jelai, a toman that would grow up to be blue color. Kept it till around 12" and yes the toman was blue color like your photo.
Very beautiful...but sadly not much study about toman species, and till now cannot find another pc like that.