Hi Neervana.
I was going to buy a blue moon galaxy at one point, but I went with a couple of Channa sp. Redfin instead.
The colors on the galaxy are gorgeous.
I believe they are a variant of Stewartii and get to around 25-30cm
They are sub tropical, but really do require low end of the sub tropical temps more than most SH.
Higher temps will simply make it an unhappy inactive SH, and it's coloring will not be as nice.
There is a few users here that own them, I'm sure they will add / correct my information.
Also, be sure it is a Blue Moon Galaxy before spending big on it, as there is so many mis-labelled "galaxies" going on!
Cheers, good luck!