The Florida Fish and Wildlife Conservation Commission rescued the tiny calf in the waters off southwest Florida, where he was found swimming all alone.
Staff say the calf weighs just 45 pounds.
"At that size he should have been seen with his mom and unfortunately she was nowhere to be found, and so it was deemed that he was needed to be rescued," a keeper with ZooTampa said.
Rescuers brought the baby to ZooTampa's Manatee Critical Care Center, which is one of only two places that takes in orphaned manatee calves.
Keepers said the young manatee is being cared for behind the scenes in their critical care pools, and being bottle-fed around the clock.
Staff anticipate that the manatee will gain about a pound a day as he grows, and they say he will be at the zoo for a couple of years until he has grown enough to potentially be released back into the wild.
According to ZooTampa, manatees must grow to about 600 pounds before they are deemed releasable.
This is the second tiny orphaned calf the zoo has helped rehabilitate in the past few months. Another baby manatee, who weighed just 44 pounds when she was rescued off the coast of Venice back in August, is also being treated in the zoo's Manatee Critical Care Center.
Also back in August, SeaWorld Orlando took in two orphaned manatee calves, and said the tiny animals need around-the-clock care, getting bottle-fed every three hours.
Anyone who sees a sick or injured manatee is asked to call FWC's hotline at 1-888-404-FWCC.