The Cano Cristales is not accessible by road; instead tourists will have to fly into La Macarena, then organise a short transfer to the Serrania de la Macarena National Park, where they can then make the last part of the journey by foot or on horseback. The Cano Cristales season runs from mid May to the start of December. It is not possible to book tours outside of these dates.
Some people mistakenly think Cano Cristales' colour comes from algae or moss. The real culprit, however, is a picky endemic aquatic plant called macarenia clavigera, which requires precise conditions, including just the right water level and just the right amount of sunlight, to take on its bright hues. Though shades of red - from pale pink to hot pink, blood red to maroon - are most common, the macarenia clavigera plant turns bright green in shaded areas. It has been seen in blue, yellow and orange as well
Cano Cristales is a fast river with many rapids and waterfalls. Often in the bed have formed small circular pits - giant's kettles, which have been formed by pebbles or chunks of harder rocks. Once one of these harder rock fragments falls into one of the cavities, it is rotated by the water current and begins to carve at the cavity wall and increases the dimensions of the pit.
The early days of Cano Cristales tourism were largely unregulated, but locals soon realized that litter from riverside picnics and other examples of human impact were threatening the macarenia clavigera, which is as delicate as lace. It wasn't uncommon to see visitors drinking alcohol on the riverbank and swimming where they pleased, even if it meant walking over the plants. Now, environmental protection rules are firmly enforced, including mandatory guides, groups of no more than seven people, a cap of 200 people per day to the area, a complete ban on wearing sunscreen or insect repellent when visiting the river and limited areas where swimming is allowed.