Hi Zsofia.  Yes, it's real, but I "punched up" the colours and contrasts somewhat in Photoshop.  It was my first RAW image, and when I began post-processing and saw the colours jump like that, I was hooked on RAW imaging forever!  I shot this photo at the Ripley's Aquarium at the foot of the CN Tower in downtown Toronto.  The last time I returned to the aquarium, however, this particular type of jellyfish was gone, sadly, as I was hoping to get an even better photo with my new camera.