A dog that is listless, lying around all the time and not eating can be caused by a variety of reasons. Here are some possible causes and suggestions:

Health problems: The dog may be sick, such as cold, Digestive problems, infections, etc. Observe your dog for other symptoms, such as vomiting, diarrhea, cough, runny nose, etc. If so, it's best to take it to a veterinarian for diagnosis and treatment.

Eating problems: The dog may not be interested in the food or there may be something wrong with the food. Try offering fresh water and dog-friendly food, or try changing food brands or flavors.

Environmental changes: Changes in the environment, such as new homes, new members, noise, etc., may have an impact on the dog's mood and behavior. Try to provide your dog with a quiet, comfortable and familiar environment.

Lack of exercise: Dogs may need more exercise to stay active and healthy. Try taking him for a walk, playing, or providing activities that are suitable for him.