(left) June 2010 Isaac Zimerman as he appeared when indicted in Los Angeles and fled the country to avoid prosecution

(right) March 3, 2015 Zimerman arrested in Metepec, Mexico

LOS ANGELES – Mexico has extradited an American citizen who formerly lived in West Hills to face federal charges related to the illegal trafficking of the world’s largest freshwater fish, a South American species known as Arapaima gigas.

Tom Mrozek, spokesman for the United States Attorney’s Office, said Isaac Zimerman, 66, arrived back in the US on Sept. 24. He was briefly hospitalized, then appeared in United States District Court in downtown Los Angeles on Monday, Sept. 28, where a judge ruled he be held without bond. Zimmerman’s next court date is pending.

Zimerman was originally charged in a 13-count indictment with using his company, the Hawthorne-based River Wonders LLC, to import piranhas and river stingrays into the United States. But, Mrozek said, the accused is currently facing only two of the felony charges related to the illegal exportation of Arapaima gigas, pursuant to the extradition treaty between the US and Mexico.

US officials are considering whether to ask Mexican officials to reconsider that decision, and enable them to try Zimerman on all 13 counts, the spokesman said.

According to investigators from the United States Fish & Wildlife Service (FWS), Zimerman allegedly possessed those fish in California, and then they were advertised for sale, sold to customers, and shipped to states outside of California.

Mrozek said the indictment also contains allegations that Zimerman engaged in additional criminal conduct related to the falsification of documents, obstruction of proceedings, false statements, and smuggling of protected Arapaima gigas from the United States while on pre-trial release.

Zimerman was initially charged in 2009, along with his company and his wife, Leonor Catalina Zimerman. While Leonor Zimerman pleaded guilty to a misdemeanor offense in 2010, Isaac Zimerman fled the United States that same year after prosecutors filed additional charges alleging that he continued to illegally export fish while on bond. Special FWS agents tracked Zimerman’s movements through Europe, to Israel and eventually to Mexico.

On March 3 of this year, concluding a four-year manhunt, Zimerman was arrested near Metepec, Mexico, Mrozek said. He said during the flight to avoid prosecution, Zimerman changed his appearance and took other steps to avoid detection and arrest.