The Gray Reef Shark was created solely by (myself) JVM... which accounts for the bad skin job. I was dissatisfied with the version available for Zoo 2 already, and in a rush to get something out for ZTH's at-the-time weekly download release. It uses the Reef biome.
It requires Zoo Tycoon 2 and the Zoo Tycoon 2: Marine Mania expansion to use ingame.