We all know ocean, lakes and seas appear blue in colour because of the reflection of the sky and generally, they have invisible colour but what if I say there are lakes which appear pink in colour sounds interesting! A pink lake is a lake that has a red or pink colour. This is often caused by salt-tolerant algae that produce carotenoids, such as Dunaliella salina, usually in conjunction with specific bacteria, which may vary from lake to lake. In some of the hundreds of Australian pink lakes, a red bacterium, Salinibacter Ruber, may be involved in producing their colour. A lake in Westgate Park, Melbourne, Australia, was coloured pink in March 2017 and then again in September 2019, but since then and as of January 2022 had taken on a dark green hue. Warmer weather and lower rainfall appear to make it turn pink. As water evaporates, the salinity increases, but salinity is not the only factor at work. Sediment and the organisms living in the lake affect its colour, and the shade of pink it takes on. Pink lakes such as Lake Hillier can be up to ten times saltier than seawater (the Dead Sea) in Israel is around nine times so. It is safe to swim in pink lakes, but it is not advisable to drink it because microorganisms present in them may harm human health. Tell me in the comments whether you want to swim in a pink lake or not.