Again in September, it was several stings from Atlantic box jellyfish that ended her quest.

CNN: Diana Nyad making fourth attempt at Cuba-to-Florida swim

She was done in once by an 11-hour asthma attack and was later thwarted by box jellyfish stings.

CNN: August 20, 2012 -- Updated 1157 GMT (1957 HKT)

From July to October, the weather is perfect for kayaking, with calm water, little rain, mild temperatures and no deadly marine stingers (such as the box jellyfish and the irukandji).

BBC: Kayaking Australia��s Whitsunday Islands

Some stings were from box jellyfish, her blog said.

CNN: August 20, 2012 -- Updated 1157 GMT (1957 HKT)

Scientists have done such experiments thousands of times, with a Crayola box of colors and using glowing genes taken from jellyfish and fireflies (see: " Biotech's Glowing Breakthrough").

FORBES: Glowing Mice From China And Other Oddities