Certified GKH Gardening Expert
This is overwatering.
Aloe will tolerate very dry conditions, so make sure that the soil is dry throughout the entire container, or just about to the very bottom, between watering.
Since it is a very small container, it should not take too long for it to get dry, but if there is any moisture when you stick your finger down in the soil, then don't water.
You may need a fungicide. This article will help:
Here is an article that will help you to care for aloe in container: