ZJX Controller expressed frustration with a MCO Air Carrier arrival experiencing fuel problems but was reluctant to declare emergency fuel; a declaration that would have simplified ATC handling.

Narrative

The BUGGZ arrival had been shut down in the GULF area due to developing thunderstorms. We received a PVD on ACR X from the R50 Sector telling us that they did not want to take a turn to the East at that time due to being low on fuel. ACR X came over to our frequency and stated that they wanted to deviate south of course to cut the corner on the arrival to MCO and we advised that we would be unable to do that due to the traffic departing off MCO. We asked the pilot about their fuel situation and said if they weren't emergency fuel and they stated to 'show us on the record as minimum fuel'. My trainee acknowledged and we passed that information onto the supervisor. A few minutes later when asked to turn out to the east to allow further descent and and avoiding traffic departing and deviating off MCO; the pilot said something along the lines of 'we have no choice' when asked about his ability to make the turn. I then over-keyed the student and told the pilot that he had only declared minimum fuel with us and that if he declared an emergency; we could handle the situation differently. The pilot only stated that it was 'going to be close' but did not declare an emergency on our frequency. We switched the aircraft to the next sector; and within 5 minutes of being there; the aircraft declared a fuel emergency. Recommendation; the pilot should have declared the emergency sooner if the fuel situation was that tight because he was told all along that he was not going to be able to be routed short on the arrival due to the current traffic flow. If the emergency had been declared earlier; the departures off of MCO could have been stopped sooner and the aircraft could have been routed directly in earlier.