Jose Salvador Alvarenga made a brief public appearance yesterday looking much weaker than he did earlier in the week.
He was greeted by 50 officials and media at the Marshall Islands Resort hotel where he is staying. Sporting a haircut and a shave, he was helped into the room by two people while others stood by ready to help.
Speaking in a low voice, he thanked the government and his friends for their help, but declined to take questions.
Mr Alvarenga's spritely appearance on Monday when he greeted hundreds of well-wishers in the capital Majuro after making landfall last week on a remote atoll had many questioning his story.
He earlier told officials he left Mexico for a day of shark fishing in late-2012 with another fisherman - who later died. However, a storm threw them off course and they began drifting.
Officials said Mr Alvarenga needed to return to hospital for more medical checks and it would be three or four days before he was fit enough to travel back to El Salvador.
Also speaking at the meeting was the Marshall Islands Foreign Minister, Phillip Muller, and Mexican diplomat Chris Clay Mendoza.
Mr Muller said the Marshall Islands was happy to do everything it could to assist Mr Alvarenga.