Damselfish and Sergeant major

Damselfish noun - Small brilliantly colored tropical marine fishes of coral reefs.

Sergeant major and damselfish are semantically related. In some cases you can replace phrase "Sergeant major" with "Damselfish", this terms are similar.

Sergeant major noun - Large blue-grey black-striped damselfish; nearly worldwide.

Damselfish and sergeant major are semantically related. Sometimes you can use "Damselfish" instead a noun phrase "Sergeant major".