"Domo" is a fictional character from the television show "The Powerpuff Girls." As a fictional character, Domo doesn't actually eat anything.
Real Animals With Similar Names
Domo (Japanese for "house"): This is not an animal but a reference to a dwelling.
"Domo" as a nickname for domestic animals: This is a possible nickname for various pets. In this case, the "domo" would eat whatever its specific species typically consumes.
Could you please clarify what kind of "domo" you're asking about?