They like it relatively cool (well the indian species do) the Thai / South east asian mahseer types prefer it slightly warmer - all like strong current and lots and lots of aeration - I currently have 6 species of mahseer - am looking for one or two more.
Not seen the blue one in the flesh but have 3 of the gold0en / red variety - they really are awesome fish
Great looking fish. Looking into this I read one forum that said that the golden mahseer (Tor putitora) is also known as the blue kelah and is blue when viewed from the top. I've seen other sites refer to the blue kelah as Tor tambroides (Malyasian mahseer). One site said that tambroides does have fin color variations which range from pink to red to blue.
There seems to be alot of confusion involving members of the genus tor. As recently as 2004 a new member was identified (Tor yingjiangensis) which had previously been mistaken for putitora.
Regardless, the large scales, subtle but striking colors, as well as the body shape and active behavior definitely makes me wish I had a mahseer swimming around my living room (in a tank of course)