RES are very cute when they sleep. They can close their eyes and sleep either under water or with their heads above the water. If under water, they have this small air bubbles on their nose. I try to keep getting a picture of Dumbork sleeping, but to no avail. RES should follow the Circadian rhythm, where they have portions of “day” and “night”. Before, we were afraid that Dumbork will get eaten by pests, or that small insects can get inside the tank, so we put his tank near a source of light. Fortunately, there’s no need for this because, like humans, they need darkness to get their share of sleep.