Country Joe McDonald, the lead singer of Country Joe and the Fish, has died.

The iconic singer, who co-founded the band known for its psychedelic folk rock and legendary 1969 Woodstock performance, died Saturday evening, TMZ reported.

His cause of death is unclear.

The singer, born Joseph Allen McDonald, was 84 years old.

Country Joe and the Fish was one of the most influential groups in the San Francisco music scene in the mid to late ’60s, addressing counterculture issues like protesting the Vietnam War and recreational drug use.

They’re known for songs like “I-Feel-Like-I’m-Fixin’-to-Die Rag,” one of the the era’s most recognizable anti-Vietnam War protest songs.

The group, founded by McDonald and Barry “The Fish” Melton, released two albums — their debut album, 1967’s “Electric Music for the Mind and Body,” and “I-Feel-Like-I’m-Fixin’-to-Die,” which came out later that year.

The band disbanded in 1971.

McDonald went on to have a solo career, and continued to release songs with political messages, highlighting environmental issues and civil rights.

He was also known for his work supporting Vietnam veterans.

He led the effort to create the Vietnam Veterans Memorial in Berkeley, Calif., and was involved in establishing the Vietnam Veterans Memorial in San Francisco.

He is survived by his wife, Kathy Wright, and reportedly had five children.