The short answer
They are the guerrab: men in red with wide, tasselled hats, goatskin water bags and polished brass cups, ringing a bell. They once sold water by the cup. Today the trade survives mostly by posing for photographs. They expect a few coins for a photo, so agree before you lift the camera; a small coin is the custom.
In more detail
The guerrab are part of the square's living heritage, alongside the storytellers, Gnawa musicians and other performers who led UNESCO to name Jemaa el-Fnaa's oral traditions a Masterpiece of the Oral and Intangible Heritage of Humanity in 2001.
Treat them as you would any performer. Ask first, agree the amount before the photo rather than after, and pay what you agreed. If you do not want a photo, a smile and 'la, shukran' is enough.
Drinking from the cups is not recommended for visitors on a short trip. Bottled water and the fresh orange juice at the busy carts are a better bet.
The square is busiest from late afternoon, when the food stalls set up, and the performers and water sellers are at their most active then. Keep your valuables secure in the crowds.
Good to know
- Keep small coins ready in the square.
- Agree the amount before you photograph.
- Drink bottled water rather than from the cups.