How do you describe a Person who does not eat meat, but eats fish?
The word demi-vegetarian appears in our file with the sense a person who eats fish but not meat, but this is not obvious as the meaning of the term and some self-styled demi-vegetarians may eat poultry and avoid only red meat.
The invented terms pesco-vegetarian and pescatarian are increasingly common and clearer in meaning. The most practical option is usually to state a person's eating preferences in an explicit phrase.