Brevard County Animal Services Capt. Bob Brown said the firefighter captured the monitor on a busy Melbourne street about 11 a.m. Tuesday and took it to a nearby pet store, Florida Today reported Wednesday.
Brown said his department does not receive many calls about monitors.
"We have one or two calls a year about monitors that get out or push the top off a container to go exploring. They're fairly hard to catch," he said.
He said monitors require state-issued permits to keep.
"We'll probably end up taking it to a shelter. You have to be very cautious handling it," Brown said.