Goldfish sleep at night. Any animal needs rest and will not be active forever, even goldfish sleep. When goldfish slow down their breathing, stop moving, and become sluggish and numb, it means they are resting and sleeping. Goldfish like to sleep in a dim environment, so every evening, they will look for opportunities to sleep.

How goldfish sleep:

1. Sleep in the dark. Before going to bed at night, goldfish will first find a dark, relatively hidden or safe place, such as among aquatic plants, behind rockeries, etc.

2. Sleep while floating. Some goldfish float motionless in the water while sleeping.

3. Sleep covered in bubbles. Some goldfish like to secrete a lot of bubbles to cover their whole body. This way they feel more secure and will not be attacked by other goldfish.

4. Get into the sand and sleep. Some goldfish like to sleep in the sand, which is quieter.