FORT WORTH — Ethan Couch was quietly moved from a juvenile detention to an adult jail facility Friday afternoon.

Juvenile Court Judge Tim Menikos told attorneys Friday morning he was moving Couch to the Tarrant County jail's maximum security unit. Even Sheriff Dee Anderson wasn't told of the transfer until just before he arrived at the unit at about 1:30 p.m.

"He is still under all the juvenile law restrictions, all that,” Anderson said in a late afternoon press conference. “He is held without bond. He cannot post bond as a juvenile."

Sheriff Anderson said Couch was processed individually as a high-profile prisoner and then placed in a single-cell for his own protection.

"Obviously, the big concern with him is that someone in the jail inmate system might want to harm him,” Anderson said.

In juvenile detention, Couch shared space with other detainees, some much younger, and many much bigger.

Couch is notorious nationwide as the “affluenza” teen. A psychologist used the phrase to help explain Couch’s behavior the night he drove drunk and killed four people.

Anderson said special efforts are being made to protect him from other inmates.

"He's getting ready to be 19,” the sheriff said. "He's an adult. He doesn't need to be housed in a juvenile detention facility. That's my opinion."

Prosecutors asked the judge to transfer Couch to adult jail last week.

Attorneys say Couch will be in juvenile court again on February 19. It's expected at that time the judge will transfer the case to adult supervision upon Couch’s 19th birthday in April.

Couch is serving 10 years probation.