Freo Today. 27 March 2021. Rottnest Island is really an extension of Fremantle. Well, we think it is! Yesterday, the Pink Lake was very pink. And thanks to Jean Hudson’s lens we are about to show you so today. The lake is pink due to the algae which is colored by natural occurring beta-carotene, and the brine shrimp turn pink from the algae intensifying the pink color. Just like pink flamingos. So there you go! Thanks Jean.