The zebra dog's head refuses to eat and always lies at the bottom of the tank. This may be caused by a variety of reasons. The following are some possible causes and corresponding solutions:

1. Water quality problems: Poor water quality may cause zebra dogs to lose appetite and reduce activity.

2. Water temperature issue: Zebra doghead fish is a tropical ornamental fish, and the water temperature suitable for living is between 25 and 28 degrees Celsius.

3. Environmental changes: Changes in the location of your home or fish tank, as well as changes in water quality, may cause stress reactions in zebra dogs.

4. Food issues: Zebra dog heads are carnivorous. If the food is not what they like, Or already overfed, they may refuse to eat.

5. Disease problems: If there are abnormalities on the zebra dog's head, such as loss of appetite, reduced activity, etc., it may be infected with bacteria or parasites. In this case, appropriate medical treatment is required.