Why does my donkey tail have white spots
Certified GKH Gardening Expert
This is likely a fungal infection. The most common cause is when the soil remains wet for too long. Make sure the soil dries out a little between watering.
The next time that you water, you can replace 1/4 of the water with peroxide. This will kill off any infection in the container. The old growth will not recover, but new growth will remain healthy. This article will help: https://www.gardeningknowhow.com/ornamental/cacti-succulents/burros-tail/burros-tail-care.htm